diff --git a/src/components/structures/auth/Registration.js b/src/components/structures/auth/Registration.js
index 1c094cf862..63c5b267cf 100644
--- a/src/components/structures/auth/Registration.js
+++ b/src/components/structures/auth/Registration.js
@@ -98,6 +98,9 @@ module.exports = React.createClass({
             // component without it.
             matrixClient: null,
 
+            // whether the HS requires an ID server to register with a threepid
+            serverRequiresIdServer: null,
+
             // The user ID we've just registered
             registeredUsername: null,
 
@@ -204,13 +207,23 @@ module.exports = React.createClass({
         }
 
         const {hsUrl, isUrl} = serverConfig;
-        this.setState({
-            matrixClient: Matrix.createClient({
-                baseUrl: hsUrl,
-                idBaseUrl: isUrl,
-            }),
+        const cli = Matrix.createClient({
+            baseUrl: hsUrl,
+            idBaseUrl: isUrl,
+        });
+
+        let serverRequiresIdServer = true;
+        try {
+            serverRequiresIdServer = await cli.doesServerRequireIdServerParam();
+        } catch (e) {
+            console.log("Unable to determine is server needs id_server param", e);
+        }
+
+        this.setState({
+            matrixClient: cli,
+            serverRequiresIdServer,
+            busy: false,
         });
-        this.setState({busy: false});
         try {
             await this._makeRegisterRequest({});
             // This should never succeed since we specified an empty
@@ -550,6 +563,7 @@ module.exports = React.createClass({
                 flows={this.state.flows}
                 serverConfig={this.props.serverConfig}
                 canSubmit={!this.state.serverErrorIsFatal}
+                serverRequiresIdServer={this.state.serverRequiresIdServer}
             />;
         }
     },
diff --git a/src/components/views/auth/RegistrationForm.js b/src/components/views/auth/RegistrationForm.js
index f3b9640e16..cf1b074fe1 100644
--- a/src/components/views/auth/RegistrationForm.js
+++ b/src/components/views/auth/RegistrationForm.js
@@ -55,6 +55,7 @@ module.exports = React.createClass({
         flows: PropTypes.arrayOf(PropTypes.object).isRequired,
         serverConfig: PropTypes.instanceOf(ValidatedServerConfig).isRequired,
         canSubmit: PropTypes.bool,
+        serverRequiresIdServer: PropTypes.bool,
     },
 
     getDefaultProps: function() {
@@ -437,7 +438,7 @@ module.exports = React.createClass({
 
     _showEmail() {
         const haveIs = Boolean(this.props.serverConfig.isUrl);
-        if (!haveIs || !this._authStepIsUsed('m.login.email.identity')) {
+        if ((this.props.serverRequiresIdServer && !haveIs) || !this._authStepIsUsed('m.login.email.identity')) {
             return false;
         }
         return true;
diff --git a/test/components/structures/auth/Registration-test.js b/test/components/structures/auth/Registration-test.js
index 6a8b35fbc0..38188b2536 100644
--- a/test/components/structures/auth/Registration-test.js
+++ b/test/components/structures/auth/Registration-test.js
@@ -69,7 +69,7 @@ describe('Registration', function() {
 
         const root = render();
 
-        // Set non-empty flow & matrixClient to get past the loading spinner
+        // Set non-empty flows & matrixClient to get past the loading spinner
         root.setState({
             flows: [],
             matrixClient: {},