diff --git a/src/parallel_io.c b/src/parallel_io.c
index 7696e7ac5b22188c9d916a96400940a1c9f7bfad..5cd6a4921a25db012b3e810c499ec151ee28391f 100644
--- a/src/parallel_io.c
+++ b/src/parallel_io.c
@@ -389,7 +389,7 @@ void read_ic_parallel(char* fileName, const struct UnitSystem* internal_units,
   long long N_total[NUM_PARTICLE_TYPES] = {0};
   long long offset[NUM_PARTICLE_TYPES] = {0};
   int dimension = 3; /* Assume 3D if nothing is specified */
-  size_t Ndm;
+  size_t Ndm = 0;
 
   /* Open file */
   /* message("Opening file '%s' as IC.", fileName); */
diff --git a/src/serial_io.c b/src/serial_io.c
index 527e294988873b01578681f82147d0161c27c777..a9be44c21dce84834397c7652e5ebb7d9c4876e4 100644
--- a/src/serial_io.c
+++ b/src/serial_io.c
@@ -440,7 +440,7 @@ void read_ic_serial(char* fileName, const struct UnitSystem* internal_units,
   long long N_total[NUM_PARTICLE_TYPES] = {0};
   long long offset[NUM_PARTICLE_TYPES] = {0};
   int dimension = 3; /* Assume 3D if nothing is specified */
-  size_t Ndm;
+  size_t Ndm = 0;
   struct UnitSystem* ic_units = malloc(sizeof(struct UnitSystem));
 
   /* First read some information about the content */
diff --git a/src/single_io.c b/src/single_io.c
index f53ad90fdcf2f997d374dbf20a416c2aa21990ae..b279f22086833bc689919f41a8904232e234a394 100644
--- a/src/single_io.c
+++ b/src/single_io.c
@@ -350,7 +350,7 @@ void read_ic_single(char* fileName, const struct UnitSystem* internal_units,
   int numParticles_highWord[NUM_PARTICLE_TYPES] = {0};
   size_t N[NUM_PARTICLE_TYPES] = {0};
   int dimension = 3; /* Assume 3D if nothing is specified */
-  size_t Ndm;
+  size_t Ndm = 0;
 
   /* Open file */
   /* message("Opening file '%s' as IC.", fileName); */