diff --git a/doc/gen_doc.py b/doc/gen_doc.py
index 61e06b4..2d13937 100644
--- a/doc/gen_doc.py
+++ b/doc/gen_doc.py
@@ -46,7 +46,7 @@ OpsWithShapeInference = [
     'LeakyRelu', 'Elu', 'Selu', 'HardSigmoid', 'Reshape', 'Reciprocal',
     'Identity', 'Cos', 'Log', 'Transpose', 'Softmax', 'ReduceMax', 'ReduceMin',
     'ReduceProd', 'ReduceSum', 'Softplus', 'Softsign', 'Sqrt', 'Unsqueeze',
-    'Sign', 'Constant', 'AveragePool', 'Abs', 'Conv'
+    'Sign', 'Constant', 'AveragePool', 'Abs', 'Conv', 'Concat'
 ]
 
 # Operations supporting canonicalization.
diff --git a/src/Dialect/ONNX/ONNXOps.cpp b/src/Dialect/ONNX/ONNXOps.cpp
index c52b6a8..cb8c8d3 100644
--- a/src/Dialect/ONNX/ONNXOps.cpp
+++ b/src/Dialect/ONNX/ONNXOps.cpp
@@ -1463,6 +1463,65 @@ bool ONNXConstantOp::inferShapes() {
   return true;
 }
 
+//===----------------------------------------------------------------------===//
+// Concat
+
+bool ONNXConcatOp::inferShapes() {
+  int inputNum = getNumOperands();
+  for (int i = 0; i < inputNum; ++i) {
+    if (!getOperand(i).getType().cast<RankedTensorType>()) {
+      emitError("Input tensor(s) not ranked");
+      return false;
+    }
+  }
+  // Checking value of axis parameter.
+  auto commonType = getOperand(0).getType().cast<RankedTensorType>();
+  auto commonShape = commonType.getShape();
+  auto commonRank = commonShape.size();
+  auto axisIndex = axis().getSExtValue();
+  if (!(axisIndex >= 0 && axisIndex < commonRank)) {
+    emitError("Concat axis value out of bound");
+    return false;
+  }
+  // Initial cummlative size is that of the first operand.
+  int cummulativeAxisSize = commonShape[axisIndex];
+
+  // Compute the cummlative size with all of the other ones, and make sure that
+  // the other sizes are all alike.
+  for (int i = 1; i < inputNum; ++i) {
+    auto currShape =
+        getOperand(i).getType().cast<RankedTensorType>().getShape();
+    if (currShape.size() != commonRank) {
+      emitError("Concat input must all have the same rank");
+      return false;
+    }
+    for (int j = 0; j < commonRank; ++j) {
+      if (j == axisIndex) {
+        // Check that the value is positive.
+        if (currShape[j] <= 0) {
+          emitError("Concat axis being concatenated is expected to be known at "
+                    "compile time for now");
+          return false;
+        }
+      } else if (currShape[j] != commonShape[j]) {
+        emitError("Concat input dimensions must be all identical, except for "
+                  "dimension on the axis of the concatenation");
+        return false;
+      }
+    }
+    cummulativeAxisSize += currShape[axisIndex];
+  }
+
+  // Set output size and type
+  SmallVector<int64_t, 4> outputDims;
+  for (int j = 0; j < commonRank; ++j)
+    outputDims.emplace_back(
+        j == axisIndex ? cummulativeAxisSize : commonShape[j]);
+  getResult().setType(
+      RankedTensorType::get(outputDims, commonType.getElementType()));
+  return true;
+}
+
 //===----------------------------------------------------------------------===//
 // TableGen'd op method definitions
 //===----------------------------------------------------------------------===//
diff --git a/src/Dialect/ONNX/ONNXOps.td.inc b/src/Dialect/ONNX/ONNXOps.td.inc
index cbf2615..20cbfaf 100644
--- a/src/Dialect/ONNX/ONNXOps.td.inc
+++ b/src/Dialect/ONNX/ONNXOps.td.inc
@@ -314,7 +314,7 @@ def ONNXCompressOp:ONNX_Op<"Compress",
 }
 
 def ONNXConcatOp:ONNX_Op<"Concat",
-  [NoSideEffect]> {
+  [NoSideEffect, DeclareOpInterfaceMethods<ShapeInferenceOpInterface>]> {
   let summary = "ONNX Concat operation";
   let description = [{
   "Concatenate a list of tensors into a single tensor. All input tensors must have the same shape, except for the dimension size of the axis to concatenate on."
diff --git a/src/Transform/ONNX/ShapeInferencePass.cpp b/src/Transform/ONNX/ShapeInferencePass.cpp
index b4385c2..2188628 100644
--- a/src/Transform/ONNX/ShapeInferencePass.cpp
+++ b/src/Transform/ONNX/ShapeInferencePass.cpp
@@ -123,6 +123,7 @@ public:
         op->getName().getStringRef() != "onnx.BatchNormalizationTestMode" &&
         op->getName().getStringRef() != "onnx.Abs" &&
         op->getName().getStringRef() != "onnx.Constant" &&
+        op->getName().getStringRef() != "onnx.Concat" &&
         op->getName().getStringRef() != "onnx.Unsqueeze")
       return false;
     return llvm::any_of(op->getResultTypes(), [](Type result_type) {
diff --git a/test/mlir/onnx/onnx_shape_inference.mlir b/test/mlir/onnx/onnx_shape_inference.mlir
index 02cf415..d44895c 100644
--- a/test/mlir/onnx/onnx_shape_inference.mlir
+++ b/test/mlir/onnx/onnx_shape_inference.mlir
@@ -487,3 +487,25 @@ func @test_reshape_3(%arg0 : tensor<5x5x1x32xf32>) -> tensor<*xf32> {
   // CHECK: [[RES:%.+]] = "onnx.Reshape"(%arg0, %0) : (tensor<5x5x1x32xf32>, tensor<3xi32>) -> tensor<80x5x2xf32>
   // CHECK: return [[RES]] : tensor<80x5x2xf32>
 }
+
+//===----------------------------------------------------------------------===//
+/// Test the reshape op inference when concat are present.
+//===----------------------------------------------------------------------===//
+
+func @test_concat_1(%arg0 : tensor<5x5x1x32xf32>, %arg1 : tensor<5x5x3x32xf32>, %arg2 : tensor<5x5x5x32xf32>) -> tensor<*xf32> {
+  %1 = "onnx.Concat"(%arg0, %arg1, %arg2) { axis = 2 } : (tensor<5x5x1x32xf32>, tensor<5x5x3x32xf32>, tensor<5x5x5x32xf32>)  -> tensor<*xf32>
+  "std.return"(%1) : (tensor<*xf32>) -> ()
+
+  // CHECK-LABEL: test_concat_1
+  // CHECK: [[RES:%.+]] = "onnx.Concat"(%arg0, %arg1, %arg2) {axis = 2 : i64} : (tensor<5x5x1x32xf32>, tensor<5x5x3x32xf32>, tensor<5x5x5x32xf32>) -> tensor<5x5x9x32xf32>
+  // CHECK: return [[RES]] : tensor<5x5x9x32xf32>
+}
+
+func @test_concat_2(%arg0 : tensor<5x1x32xf32>, %arg1 : tensor<5x3x32xf32>, %arg2 : tensor<5x5x32xf32>) -> tensor<*xf32> {
+  %1 = "onnx.Concat"(%arg0, %arg1, %arg2) { axis = 1 } : (tensor<5x1x32xf32>, tensor<5x3x32xf32>, tensor<5x5x32xf32>)  -> tensor<*xf32>
+  "std.return"(%1) : (tensor<*xf32>) -> ()
+
+  // CHECK-LABEL: test_concat_2
+  // CHECK: [[RES:%.+]] = "onnx.Concat"(%arg0, %arg1, %arg2) {axis = 1 : i64} : (tensor<5x1x32xf32>, tensor<5x3x32xf32>, tensor<5x5x32xf32>) -> tensor<5x9x32xf32>
+  // CHECK: return [[RES]] : tensor<5x9x32xf32>
+}