diff --git a/Cargo.lock b/Cargo.lock
index 3d259b3f..8f4a5031 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -147,6 +147,19 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "time",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "clap"
 version = "2.33.3"
@@ -399,7 +412,7 @@ checksum = "4060f4657be78b8e766215b02b18a2e862d83745545de804638e2b545e81aee6"
 dependencies = [
  "cfg-if 1.0.0",
  "libc",
- "wasi 0.10.1+wasi-snapshot-preview1",
+ "wasi 0.10.0+wasi-snapshot-preview1",
 ]
 
 [[package]]
@@ -681,6 +694,16 @@ dependencies = [
  "itoa",
 ]
 
+[[package]]
+name = "num-integer"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.14"
@@ -785,6 +808,7 @@ dependencies = [
 name = "py-spy"
 version = "0.3.4"
 dependencies = [
+ "chrono",
  "clap",
  "console 0.13.0",
  "cpp_demangle",
@@ -1188,6 +1212,17 @@ dependencies = [
  "lazy_static",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "tiny-keccak"
 version = "2.0.2"
@@ -1235,9 +1270,9 @@ checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 
 [[package]]
 name = "wasi"
-version = "0.10.1+wasi-snapshot-preview1"
+version = "0.10.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93c6c3420963c5c64bca373b25e77acb562081b9bb4dd5bb864187742186cea9"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
 
 [[package]]
 name = "wasmparser"
diff --git a/Cargo.toml b/Cargo.toml
index 505e1421..017dc70a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,6 +34,7 @@ serde_json = "1.0"
 rand = "0.8"
 rand_distr = "0.4"
 remoteprocess = {version="0.4.2", features=["unwind"]}
+chrono = "0.4.19"
 
 [target.'cfg(unix)'.dependencies]
 termios = "0.3.2"
diff --git a/src/config.rs b/src/config.rs
index 84ecbdf0..30287dac 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -143,7 +143,7 @@ impl Config {
                 .value_name("filename")
                 .help("Output filename")
                 .takes_value(true)
-                .required(true))
+                .required(false))
             .arg(Arg::with_name("format")
                 .short("f")
                 .long("format")
diff --git a/src/main.rs b/src/main.rs
index e47c98c2..0435eb1c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,6 +13,7 @@ extern crate lazy_static;
 extern crate libc;
 #[macro_use]
 extern crate log;
+extern crate chrono;
 #[cfg(unwind)]
 extern crate lru;
 extern crate memmap;
@@ -66,6 +67,8 @@ use stack_trace::{StackTrace, Frame};
 use console_viewer::ConsoleViewer;
 use config::{Config, FileFormat, RecordDuration};
 
+use chrono::{SecondsFormat, Local};
+
 #[cfg(unix)]
 fn permission_denied(err: &Error) -> bool {
     err.iter_chain().any(|cause| {
@@ -153,9 +156,25 @@ fn record_samples(pid: remoteprocess::Pid, config: &Config) -> Result<(), Error>
         None => return Err(format_err!("A file format is required to record samples"))
     };
 
-    let filename = match config.filename.as_ref() {
+    let filename = match config.filename.clone() {
         Some(filename) => filename,
-        None => return Err(format_err!("A filename is required to record samples"))
+        None => {
+            let ext = match config.format.as_ref() {
+                Some(FileFormat::flamegraph) => "svg",
+                Some(FileFormat::speedscope) => "json",
+                Some(FileFormat::raw) => "txt",
+                None => return Err(format_err!("A file format is required to record samples"))
+            };
+            let local_time = Local::now().to_rfc3339_opts(SecondsFormat::Secs, true);
+            let name = match config.python_program.as_ref() {
+                Some(prog) => prog[0].to_string(),
+                None  => match config.pid.as_ref() {
+                    Some(pid) => pid.to_string(),
+                    None => String::from("unknown")
+                }
+            };
+            format!("{}-{}.{}", name, local_time, ext)
+            }
     };
 
     let sampler = sampler::Sampler::new(pid, config)?;
@@ -294,7 +313,7 @@ fn record_samples(pid: remoteprocess::Pid, config: &Config) -> Result<(), Error>
     }
 
     {
-    let mut out_file = std::fs::File::create(filename)?;
+    let mut out_file = std::fs::File::create(&filename)?;
     output.write(&mut out_file)?;
     }
 
@@ -305,7 +324,7 @@ fn record_samples(pid: remoteprocess::Pid, config: &Config) -> Result<(), Error>
             // you might be SSH'ed into a server somewhere and this isn't desired, but on
             // that is pretty unlikely for osx) (note to self: xdg-open will open on linux)
             #[cfg(target_os = "macos")]
-            std::process::Command::new("open").arg(filename).spawn()?;
+            std::process::Command::new("open").arg(&filename).spawn()?;
         },
         FileFormat::speedscope =>  {
             println!("{}Wrote speedscope file to '{}'. Samples: {} Errors: {}", lede, filename, samples, errors);