diff --git a/OSBindings/Qt/mainwindow.cpp b/OSBindings/Qt/mainwindow.cpp
index 39a1b646a..6eae7d315 100644
--- a/OSBindings/Qt/mainwindow.cpp
+++ b/OSBindings/Qt/mainwindow.cpp
@@ -1069,7 +1069,11 @@ void MainWindow::start_atariST() {
 	using Target = Analyser::Static::AtariST::Target;
 	auto target = std::make_unique<Target>();
 
-	/* There are no options yet for an Atari ST. */
+	switch(ui->atariSTRAMComboBox->currentIndex()) {
+		default:	target->memory_size = Target::MemorySize::FiveHundredAndTwelveKilobytes;	break;
+		case 1:		target->memory_size = Target::MemorySize::OneMegabyte;						break;
+		case 2:		target->memory_size = Target::MemorySize::FourMegabytes;					break;
+	}
 
 	launchTarget(std::move(target));
 }
@@ -1274,7 +1278,8 @@ void MainWindow::launchTarget(std::unique_ptr<Analyser::Static::Target> &&target
 	/* Amstrad CPC. */													\
 	ComboBox(amstradCPCModelComboBox, "amstradcpc.model");				\
 																		\
-	/* Atari ST: nothing */												\
+	/* Atari ST. */														\
+	ComboBox(atariSTRAMComboBox, "atarist.memorySize");					\
 																		\
 	/* Electron. */														\
 	CheckBox(electronDFSCheckBox, "electron.hasDFS");					\
diff --git a/OSBindings/Qt/mainwindow.ui b/OSBindings/Qt/mainwindow.ui
index 3d05cc783..511df37ea 100644
--- a/OSBindings/Qt/mainwindow.ui
+++ b/OSBindings/Qt/mainwindow.ui
@@ -343,12 +343,39 @@
         <string>Atari ST</string>
        </attribute>
        <layout class="QVBoxLayout">
-        <item alignment="Qt::AlignTop">
-         <widget class="QLabel">
-          <property name="text">
-           <string>At present only a 512k Atari ST is supported.</string>
-          </property>
-         </widget>
+        <item>
+         <layout class="QHBoxLayout">
+          <item>
+           <layout class="QFormLayout">
+            <item row="0" column="0">
+             <widget class="QLabel">
+              <property name="text">
+               <string>RAM:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="0" column="1">
+             <widget class="QComboBox" name="atariSTRAMComboBox">
+              <item>
+               <property name="text">
+                <string>512 kb</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>1 mb</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>4 mb</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+           </layout>
+          </item>
+         </layout>
         </item>
        </layout>
       </widget>