diff --git a/src/cortex-cli/src/stats_cmd.rs b/src/cortex-cli/src/stats_cmd.rs
index 1e407503..b43cc867 100644
--- a/src/cortex-cli/src/stats_cmd.rs
+++ b/src/cortex-cli/src/stats_cmd.rs
@@ -330,7 +330,7 @@ fn infer_provider(model: &str) -> String {
 }
 
 /// Collect statistics from session files.
-async fn collect_stats(sessions_dir: &PathBuf, cli: &StatsCli) -> Result<UsageStats> {
+pub(super) async fn collect_stats(sessions_dir: &PathBuf, cli: &StatsCli) -> Result<UsageStats> {
     let mut stats = UsageStats::default();
 
     // Calculate date range
@@ -363,10 +363,15 @@ async fn collect_stats(sessions_dir: &PathBuf, cli: &StatsCli) -> Result<UsageSt
         // Try to parse the session
         if let Ok(session_data) = parse_session_file(&path) {
             // Check if session is within date range
-            if let Some(ref timestamp) = session_data.timestamp
-                && let Ok(session_date) = chrono::DateTime::parse_from_rfc3339(timestamp)
-                && session_date < start_date
-            {
+            let Some(session_date) = session_data
+                .timestamp
+                .as_deref()
+                .and_then(|timestamp| chrono::DateTime::parse_from_rfc3339(timestamp).ok())
+            else {
+                continue;
+            };
+
+            if session_date < start_date {
                 continue;
             }
 
diff --git a/src/cortex-cli/tests/stats_days_timestamp_filter.rs b/src/cortex-cli/tests/stats_days_timestamp_filter.rs
new file mode 100644
index 00000000..d2aadd94
--- /dev/null
+++ b/src/cortex-cli/tests/stats_days_timestamp_filter.rs
@@ -0,0 +1,57 @@
+use serde_json::json;
+
+#[path = "../src/stats_cmd.rs"]
+mod stats_cmd;
+
+fn write_session(
+    sessions_dir: &std::path::Path,
+    name: &str,
+    timestamp: Option<&str>,
+    input_tokens: u64,
+) {
+    let mut session = json!({
+        "model": "gpt-4o",
+        "usage": {
+            "input_tokens": input_tokens,
+            "output_tokens": 1
+        }
+    });
+
+    if let Some(timestamp) = timestamp {
+        session["timestamp"] = json!(timestamp);
+    }
+
+    std::fs::write(
+        sessions_dir.join(name),
+        serde_json::to_string_pretty(&session).expect("serialize session"),
+    )
+    .expect("write session");
+}
+
+#[tokio::test]
+async fn stats_days_ignores_sessions_without_parseable_timestamps() {
+    let temp = tempfile::tempdir().expect("temp dir");
+    let sessions_dir = temp.path().join("sessions");
+    std::fs::create_dir_all(&sessions_dir).expect("create sessions dir");
+
+    let recent_timestamp = chrono::Utc::now().to_rfc3339();
+    write_session(&sessions_dir, "recent.json", Some(&recent_timestamp), 10);
+    write_session(&sessions_dir, "old.json", Some("2000-01-01T00:00:00Z"), 100);
+    write_session(&sessions_dir, "invalid.json", Some("not-a-date"), 1_000);
+    write_session(&sessions_dir, "missing.json", None, 10_000);
+
+    let cli = stats_cmd::StatsCli {
+        days: 1,
+        provider: None,
+        model: None,
+        json: true,
+        verbose: false,
+    };
+    let stats = stats_cmd::collect_stats(&sessions_dir, &cli)
+        .await
+        .expect("collect stats");
+
+    assert_eq!(stats.total_sessions, 1);
+    assert_eq!(stats.input_tokens, 10);
+    assert_eq!(stats.output_tokens, 1);
+}