diff --git a/blocksworld/README b/blocksworld/README
index 5dcd0a1b6..8789baf71 100644
--- a/blocksworld/README
+++ b/blocksworld/README
@@ -4,12 +4,12 @@ subdirectory. The directories 3ops/2pddl and 4ops/2pddl contain
 programs that translate the generator's output to PDDL. The random
 instances can then be generated by running the script
 
-./blocksworld <ops> <num>
+./blocksworld <ops> <num> <seed>
 
-which takes as input the number of operators (either 3 or 4) and blocks
-in the problem to be generated. This is currently maximal 200 due to
-the random state generator. To increase that, edit the Makefile in
-bwstates.1 and increase SIZE.
+which takes as input the number of operators (either 3 or 4), blocks
+in the problem to be generated, and a random seed for reproducibility.
+The number of blocks is currently limited to 200 due to the random state generator.
+To increase that, edit the Makefile in bwstates.1 and increase SIZE.
 
 ## Blocksworld-3ops
 
diff --git a/blocksworld/blocksworld b/blocksworld/blocksworld
index 74f282313..0ee021cf3 100755
--- a/blocksworld/blocksworld
+++ b/blocksworld/blocksworld
@@ -4,6 +4,7 @@ set -euo pipefail
 
 OPS=$1  # Either 3 or 4.
 BLOCKS=$2
+SEED=$3
 
 # Get full directory name of the script (https://stackoverflow.com/a/246128).
 SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
@@ -11,7 +12,7 @@ SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 BS=${SCRIPT_DIR}/bwstates.1/bwstates
 TR=${SCRIPT_DIR}/${OPS}ops/2pddl/2pddl
 
-${BS} -s 2 -n ${BLOCKS} > STATES
+${BS} -s 2 -n ${BLOCKS} -r ${SEED} > STATES
 ${TR} -d STATES -n ${BLOCKS}
 
 rm STATES
diff --git a/blocksworld/matching/README.txt b/blocksworld/matching/README.txt
index 617208413..f528b6c79 100644
--- a/blocksworld/matching/README.txt
+++ b/blocksworld/matching/README.txt
@@ -15,10 +15,10 @@ You also need to make sure that the shell script is executable via:
 
   chmod +x matching-bw-generator.sh
 
-Then to generate a matching-bw problem with base name "bname" and size
-"n" you can call:
+Then to generate a matching-bw problem with base name "bname", size
+"n", and random seed "s" you can call:
 
-  ./matching-bw-generator.sh bname n
+  ./matching-bw-generator.sh bname n s
 
 This will create two files: bname-typed.pddl and bname-untyped.pddl
 
diff --git a/blocksworld/matching/matching-bw-generator.sh b/blocksworld/matching/matching-bw-generator.sh
index 50a335ae0..42c32d6dd 100755
--- a/blocksworld/matching/matching-bw-generator.sh
+++ b/blocksworld/matching/matching-bw-generator.sh
@@ -6,8 +6,8 @@ set -euo pipefail
 
 cd "$(dirname "$0")"
 
-./../bwstates.1/bwstates -n $2 > temp.blocks || true
-./../bwstates.1/bwstates -n $2 >> temp.blocks || true
+./../bwstates.1/bwstates -n $2 -r $3 > temp.blocks || true
+./../bwstates.1/bwstates -n $2 -r $3 >> temp.blocks || true
 
 ./2pddl-typed -d temp.blocks -n $2 > $1-typed.pddl
 ./2pddl-untyped -d temp.blocks -n $2 > $1-untyped.pddl