diff --git a/conda/environment.yml b/conda/environment.yml
index 318eada..0e232f4 100644
--- a/conda/environment.yml
+++ b/conda/environment.yml
@@ -4,5 +4,6 @@ channels:
   - httomo
 dependencies:
   - conda-forge::cuda-version
+  - conda-forge::numpy<2
   - conda-forge::pyyaml
   - conda-forge::tomopy=1.15
diff --git a/pyproject.toml b/pyproject.toml
index 0f54607..43ac216 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,7 +47,7 @@ classifiers = [
 
 requires-python = ">=3.10"
 dependencies = [
-    "numpy",
+    "numpy<2",
     "pyyaml",
     "tomopy",
     "cupy-cuda12x==12.3.0",