diff --git a/src/commands/README.md b/src/commands/README.md
new file mode 100644
index 000000000..61c515e7b
--- /dev/null
+++ b/src/commands/README.md
@@ -0,0 +1 @@
+# Commands
diff --git a/src/commands/cornerstone.js b/src/commands/cornerstone.js
new file mode 100644
index 000000000..ab8974ea4
--- /dev/null
+++ b/src/commands/cornerstone.js
@@ -0,0 +1,169 @@
+import cornerstone from 'cornerstone-core';
+
+const definitions = {
+  rotateViewportCW: {
+    commandFn: actions.rotateViewport,
+    storeContexts: ['viewports'],
+    options: { rotation: 90 },
+  },
+  rotateViewportCCW: {
+    commandFn: actions.rotateViewport,
+    storeContexts: ['viewports'],
+    options: { rotation: -90 },
+  },
+  invertViewport: {
+    commandFn: actions.invertViewport,
+    storeContexts: ['viewports'],
+    options: {},
+  },
+  flipViewportVertical: {
+    commandFn: actions.flipViewportVertical,
+    storeContexts: ['viewports'],
+    options: {},
+  },
+  flipViewportHorizontal: {
+    commandFn: actions.flipViewportHorizontal,
+    storeContexts: ['viewports'],
+    options: {},
+  },
+  scaleUpViewport: {
+    keys: '',
+    commandFn: actions.scaleViewport,
+    storeContexts: ['viewports'],
+    options: { direction: 1 },
+  },
+  scaleDownViewport: {
+    keys: '',
+    commandFn: actions.scaleViewport,
+    storeContexts: ['viewports'],
+    options: { direction: -1 },
+  },
+  fitViewportToWindow: {
+    commandFn: actions.scaleViewport,
+    storeContexts: ['viewports'],
+    options: { direction: 0 },
+  },
+  resetViewport: {
+    commandFn: actions.resetViewport,
+    storeContexts: ['viewports'],
+    options: {},
+  },
+  // TODO: Clear Annotations
+  // TODO: Next/Previous image
+  // TODO: First/Last image
+  // Next/Previous series/DisplaySet
+  nextViewportDisplaySet: {
+    commandFn: actions.updateViewportDisplaySet,
+    storeContexts: [],
+    options: { direction: 1 },
+  },
+  previousViewportDisplaySet: {
+    commandFn: actions.updateViewportDisplaySet,
+    storeContexts: [],
+    options: { direction: 1 },
+  },
+};
+
+const actions = {
+  rotateViewport: ({ viewports, rotation }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+
+    if (enabledElement) {
+      let viewport = cornerstone.getViewport(enabledElement);
+      viewport.rotation += rotation;
+      cornerstone.setViewport(enabledElement, viewport);
+    }
+  },
+  flipViewportHorizontal: ({ viewports }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+
+    if (enabledElement) {
+      let viewport = cornerstone.getViewport(enabledElement);
+      viewport.hflip = !viewport.hflip;
+      cornerstone.setViewport(enabledElement, viewport);
+    }
+  },
+  flipViewportVertical: ({ viewports }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+
+    if (enabledElement) {
+      let viewport = cornerstone.getViewport(enabledElement);
+      viewport.vflip = !viewport.vflip;
+      cornerstone.setViewport(enabledElement, viewport);
+    }
+  },
+  scaleViewport: ({ viewports, direction }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+    const step = direction * 0.15;
+
+    if (enabledElement) {
+      if (step) {
+        let viewport = cornerstone.getViewport(enabledElement);
+        viewport.scale += step;
+        cornerstone.setViewport(enabledElement, viewport);
+      } else {
+        cornerstone.fitToWindow(enabledElement);
+      }
+    }
+  },
+  resetViewport: ({ viewports }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+
+    if (enabledElement) {
+      cornerstone.reset(enabledElement);
+    }
+  },
+
+  invertViewport: ({ viewports }) => {
+    const enabledElement = _getActiveViewportEnabledElement(
+      viewports.viewportSpecificData,
+      viewports.activeViewportIndex
+    );
+
+    if (enabledElement) {
+      let viewport = cornerstone.getViewport(enabledElement);
+      viewport.invert = !viewport.invert;
+      cornerstone.setViewport(enabledElement, viewport);
+    }
+  },
+  updateViewportDisplaySet: ({ direction }) => {
+    // TODO
+    console.warn('updateDisplaySet: ', direction);
+  },
+  clearAnnotations: () => {
+    console.warn('clearAnnotations: not yet implemented');
+    // const toolState =
+    //   cornerstoneTools.globalImageIdSpecificToolStateManager.toolState;
+    // if (!toolState) return;
+    // Object.keys(toolState).forEach(imageId => {
+    //   if (!cornerstoneImageId || cornerstoneImageId === imageId)
+    //     delete toolState[imageId];
+    // });
+  },
+};
+
+/**
+ * Grabs `dom` reference for the enabledElement of
+ * the active viewport
+ */
+function _getActiveViewportEnabledElement(viewports, activeIndex) {
+  const activeViewport = viewports[activeIndex] || {};
+  return activeViewport.dom;
+}
+
+export default definitions;
diff --git a/src/commands/index.js b/src/commands/index.js
new file mode 100644
index 000000000..b577eb2b8
--- /dev/null
+++ b/src/commands/index.js
@@ -0,0 +1,52 @@
+import { CommandsManager } from 'ohif-core';
+import cornerstoneCommandDefinitions from 'cornerstone.js';
+import viewerCommandDefinitions from 'viewer.js';
+
+const CONTEXTS = {
+  viewer: 'VIEWER',
+  cornerstone: 'VIEWER::CORNERSTONE',
+};
+
+/**
+ * Register all commands
+ */
+function init() {
+  _registerViewerCommands();
+  _registerCornerstoneCommands();
+}
+
+/**
+ * Register all Viewer commands
+ *
+ * @private
+ */
+function _registerViewerCommands() {
+  const commandContext = CONTEXTS.viewer;
+
+  CommandsManager.createContext(commandContext);
+  Object.keys(viewerCommandDefinitions).forEach(commandName => {
+    const commandDefinition = viewerCommandDefinitions[commandName];
+
+    CommandsManager.register(commandContext, commandName, commandDefinition);
+  });
+}
+
+/**
+ * Register all Cornerstone commands
+ *
+ * @private
+ */
+function _registerCornerstoneCommands() {
+  const commandContext = CONTEXTS.cornerstone;
+
+  CommandsManager.createContext(commandContext);
+  Object.keys(cornerstoneCommandDefinitions).forEach(commandName => {
+    const commandDefinition = cornerstoneCommandDefinitions[commandName];
+
+    CommandsManager.register(commandContext, commandName, commandDefinition);
+  });
+}
+
+export default {
+  init,
+};
diff --git a/src/commands/viewer.js b/src/commands/viewer.js
new file mode 100644
index 000000000..7f0bc0f4d
--- /dev/null
+++ b/src/commands/viewer.js
@@ -0,0 +1,36 @@
+import { redux } from 'ohif-core';
+import store from './store';
+const { setViewportActive } = redux.actions;
+
+const definitions = {
+  // Next/Previous active viewport
+  incrementActiveViewport: {
+    commandFn: actions.updateActiveViewport,
+    storeContexts: ['viewports'],
+    options: { direction: 1 },
+  },
+  decrementActiveViewport: {
+    commandFn: actions.updateActiveViewport,
+    storeContexts: ['viewports'],
+    options: { direction: -1 },
+  },
+};
+
+const actions = {
+  updateViewportDisplaySet: ({ direction }) => {
+    // TODO
+    console.warn('updateDisplaySet: ', direction);
+  },
+  updateActiveViewport: ({ viewports, direction }) => {
+    const { viewportSpecificData, activeViewportIndex } = viewports;
+    const maxIndex = Object.keys(viewportSpecificData).length - 1;
+
+    let newIndex = activeViewportIndex + direction;
+    newIndex = newIndex > maxIndex ? 0 : newIndex;
+    newIndex = newIndex < 0 ? maxIndex : newIndex;
+
+    store.dispatch(setViewportActive(newIndex));
+  },
+};
+
+export default definitions;