diff --git a/src/main.rs b/src/main.rs
index 576ac2313..c114ba9dc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,6 +31,12 @@ fn main() {
                 .help("Number of virtual CPUs")
                 .takes_value(true),
         )
+        .arg(
+            Arg::with_name("memory")
+                .long("memory")
+                .help("Amount of RAM (in MB)")
+                .takes_value(true),
+        )
         .get_matches();
 
     let kernel_arg = cmd_arguments
@@ -45,10 +51,15 @@ fn main() {
         vcpus = cpus.parse::<u8>().unwrap();
     }
 
-    println!("VM [{} vCPUS]", vcpus);
+    let mut memory = DEFAULT_MEMORY;
+    if let Some(mem) = cmd_arguments.value_of("memory") {
+        memory = mem.parse::<u64>().unwrap();
+    }
+
+    println!("VM [{} vCPUS {} MB of memory]", vcpus, memory);
     println!("Booting {:?}...", kernel_path);
 
-    let vm_config = VmConfig::new(kernel_path, vcpus).unwrap();
+    let vm_config = VmConfig::new(kernel_path, vcpus, memory).unwrap();
 
     vmm::boot_kernel(vm_config).unwrap();
 }
diff --git a/vmm/src/vm.rs b/vmm/src/vm.rs
index 34142da53..72522b3ff 100644
--- a/vmm/src/vm.rs
+++ b/vmm/src/vm.rs
@@ -31,6 +31,7 @@ use vmm_sys_util::EventFd;
 
 const VCPU_RTSIG_OFFSET: i32 = 0;
 pub const DEFAULT_VCPUS: u8 = 1;
+pub const DEFAULT_MEMORY: GuestUsize = 512;
 const DEFAULT_CMDLINE: &str = "console=ttyS0 reboot=k panic=1 pci=off nomodules \
                                i8042.noaux i8042.nomux i8042.nopnp i8042.dumbkbd";
 const CMDLINE_OFFSET: GuestAddress = GuestAddress(0x20000);
@@ -168,9 +169,10 @@ pub struct VmConfig<'a> {
 }
 
 impl<'a> VmConfig<'a> {
-    pub fn new(kernel_path: &'a Path, vcpus: u8) -> Result<Self> {
+    pub fn new(kernel_path: &'a Path, vcpus: u8, memory_size: GuestUsize) -> Result<Self> {
         Ok(VmConfig {
             kernel_path,
+            memory_size,
             vcpu_count: vcpus,
             ..Default::default()
         })
@@ -187,8 +189,8 @@ impl<'a> Default for VmConfig<'a> {
             kernel_path: Path::new(""),
             cmdline: Some(cmdline),
             cmdline_addr: CMDLINE_OFFSET,
-            memory_size: 512,
-            vcpu_count: 1,
+            memory_size: DEFAULT_MEMORY,
+            vcpu_count: DEFAULT_VCPUS,
         }
     }
 }