diff --git a/pypesto/optimize/ess/sacess.py b/pypesto/optimize/ess/sacess.py
index 7b8cde97d..34b5941ec 100644
--- a/pypesto/optimize/ess/sacess.py
+++ b/pypesto/optimize/ess/sacess.py
@@ -7,7 +7,9 @@
 import time
 from multiprocessing import Manager, Process
 from multiprocessing.managers import SyncManager
-from typing import Any, Dict, List, Optional, Tuple
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple, Union
+from uuid import uuid1
 from warnings import warn
 
 import numpy as np
@@ -49,6 +51,7 @@ def __init__(
         max_walltime_s: float = np.inf,
         sacess_loglevel: int = logging.INFO,
         ess_loglevel: int = logging.WARNING,
+        tmpdir: Union[Path, str] = None,
     ):
         """Construct.
 
@@ -75,6 +78,11 @@ def __init__(
             Loglevel for ESS runs.
         sacess_loglevel:
             Loglevel for SACESS runs.
+        tmpdir:
+            Directory for temporary files. Defaults to a directory in the current
+            working directory named ``SacessOptimizerTemp-{random suffix}``.
+            When setting this option, make sure any optimizers running in parallel
+            have unique tmpdirs.
         """
         if (num_workers is None and ess_init_args is None) or (
             num_workers is not None and ess_init_args is not None
@@ -96,6 +104,13 @@ def __init__(
         self.sacess_loglevel = sacess_loglevel
         logger.setLevel(self.sacess_loglevel)
 
+        self._tmpdir = tmpdir
+        if self._tmpdir is None:
+            while self._tmpdir is None or self._tmpdir.exists():
+                self._tmpdir = Path(f"SacessOptimizerTemp-{str(uuid1())[:8]}")
+        self._tmpdir = Path(self._tmpdir).absolute()
+        self._tmpdir.mkdir(parents=True, exist_ok=True)
+
     def minimize(
         self,
         problem: Problem,
@@ -141,12 +156,15 @@ def minimize(
                 SacessWorker(
                     manager=sacess_manager,
                     ess_kwargs=ess_kwargs,
-                    worker_idx=i,
+                    worker_idx=worker_idx,
                     max_walltime_s=self.max_walltime_s,
                     loglevel=self.sacess_loglevel,
                     ess_loglevel=self.ess_loglevel,
+                    tmp_result_file=SacessWorker.get_temp_result_filename(
+                        worker_idx, self._tmpdir
+                    ),
                 )
-                for i, ess_kwargs in enumerate(ess_init_args)
+                for worker_idx, ess_kwargs in enumerate(ess_init_args)
             ]
             # launch worker processes
             worker_processes = [
@@ -187,7 +205,7 @@ def _create_result(self, problem: Problem) -> pypesto.Result:
         result = None
         for worker_idx in range(self.num_workers):
             tmp_result_filename = SacessWorker.get_temp_result_filename(
-                worker_idx
+                worker_idx, self._tmpdir
             )
             try:
                 tmp_result = read_result(
@@ -210,10 +228,16 @@ def _create_result(self, problem: Problem) -> pypesto.Result:
                 )
 
         # delete temporary files only after successful consolidation
-        for filename in map(
-            SacessWorker.get_temp_result_filename, range(self.num_workers)
-        ):
+        for worker_idx in range(self.num_workers):
+            filename = SacessWorker.get_temp_result_filename(
+                worker_idx, self._tmpdir
+            )
             os.remove(filename)
+        # delete tmpdir if empty
+        try:
+            self._tmpdir.rmdir()
+        except OSError:
+            pass
 
         result.optimize_result.sort()
 
@@ -380,6 +404,7 @@ class SacessWorker:
     _logger: A Logger instance.
     _loglevel: Logging level for sacess
     _ess_loglevel: Logging level for ESS runs
+    _tmp_result_file: Path of a temporary file to be created.
     """
 
     def __init__(
@@ -390,6 +415,7 @@ def __init__(
         max_walltime_s: float = np.inf,
         loglevel: int = logging.INFO,
         ess_loglevel: int = logging.WARNING,
+        tmp_result_file: str = None,
     ):
         self._manager = manager
         self._worker_idx = worker_idx
@@ -404,6 +430,7 @@ def __init__(
         self._loglevel = loglevel
         self._ess_loglevel = ess_loglevel
         self._logger = None
+        self._tmp_result_file = tmp_result_file
 
     def run(
         self,
@@ -458,12 +485,13 @@ def run(
             ess_results.optimize_result.list = (
                 ess_results.optimize_result.list[:50]
             )
-            write_result(
-                ess_results,
-                self.get_temp_result_filename(self._worker_idx),
-                overwrite=True,
-                optimize=True,
-            )
+            if self._tmp_result_file:
+                write_result(
+                    ess_results,
+                    self._tmp_result_file,
+                    overwrite=True,
+                    optimize=True,
+                )
             # check if the best solution of the last local ESS is sufficiently
             # better than the sacess-wide best solution
             self.maybe_update_best(ess.x_best, ess.fx_best)
@@ -608,8 +636,10 @@ def _keep_going(self):
         return True
 
     @staticmethod
-    def get_temp_result_filename(worker_idx: int) -> str:
-        return f"sacess-{worker_idx:02d}_tmp.h5"
+    def get_temp_result_filename(
+        worker_idx: int, tmpdir: Union[str, Path]
+    ) -> str:
+        return str(Path(tmpdir, f"sacess-{worker_idx:02d}_tmp.h5").absolute())
 
 
 def _run_worker(