diff --git a/crypto_kem/frodokem1344aes/clean/noise.c b/crypto_kem/frodokem1344aes/clean/noise.c
index d83162bc..159506d8 100644
--- a/crypto_kem/frodokem1344aes/clean/noise.c
+++ b/crypto_kem/frodokem1344aes/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM1344AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem1344shake/clean/noise.c b/crypto_kem/frodokem1344shake/clean/noise.c
index decce08a..a49dfc17 100644
--- a/crypto_kem/frodokem1344shake/clean/noise.c
+++ b/crypto_kem/frodokem1344shake/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM1344SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem640aes/clean/noise.c b/crypto_kem/frodokem640aes/clean/noise.c
index 2221219e..21ffcad8 100644
--- a/crypto_kem/frodokem640aes/clean/noise.c
+++ b/crypto_kem/frodokem640aes/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM640AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem640shake/clean/noise.c b/crypto_kem/frodokem640shake/clean/noise.c
index 08c975d5..9926a787 100644
--- a/crypto_kem/frodokem640shake/clean/noise.c
+++ b/crypto_kem/frodokem640shake/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM640SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem976aes/clean/noise.c b/crypto_kem/frodokem976aes/clean/noise.c
index 45d868ed..6fdc30f6 100644
--- a/crypto_kem/frodokem976aes/clean/noise.c
+++ b/crypto_kem/frodokem976aes/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM976AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem976shake/clean/noise.c b/crypto_kem/frodokem976shake/clean/noise.c
index b2b4f2dc..c13b4cad 100644
--- a/crypto_kem/frodokem976shake/clean/noise.c
+++ b/crypto_kem/frodokem976shake/clean/noise.c
@@ -16,7 +16,8 @@ void PQCLEAN_FRODOKEM976SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i;
+    unsigned int j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;