diff --git a/src/primaite/session/environment.py b/src/primaite/session/environment.py
index 0fd21b9f..9054106e 100644
--- a/src/primaite/session/environment.py
+++ b/src/primaite/session/environment.py
@@ -62,6 +62,13 @@ def set_random_seed(seed: int, generate_seed_value: bool) -> Union[None, int]:
     return seed
 
 
+def log_seed_value(seed: int):
+    """Log the selected seed value to file."""
+    path = SIM_OUTPUT.path / "seed.log"
+    with open(path, "w") as file:
+        file.write(f"Seed value = {seed}")
+
+
 class PrimaiteGymEnv(gymnasium.Env):
     """
     Thin wrapper env to provide agents with a gymnasium API.
@@ -92,6 +99,8 @@ class PrimaiteGymEnv(gymnasium.Env):
 
         _LOGGER.info(f"PrimaiteGymEnv RNG seed = {self.seed}")
 
+        log_seed_value(self.seed)
+
     def action_masks(self) -> np.ndarray:
         """
         Return the action mask for the agent.