diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -40,8 +40,11 @@
 #include "mlir/Dialect/Complex/IR/Complex.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Dialect/Math/IR/Math.h"
+#include "llvm/ADT/APFloat.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/MathExtras.h"
+#include <mlir/IR/BuiltinTypes.h>
 #include <optional>
 
 #define DEBUG_TYPE "flang-lower-intrinsic"
@@ -179,6 +182,7 @@
                                   llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genAnint(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genAny(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
+  mlir::Value genAtand(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue
       genCommandArgumentCount(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genAssociated(mlir::Type,
@@ -485,6 +489,7 @@
      &I::genAssociated,
      {{{"pointer", asInquired}, {"target", asInquired}}},
      /*isElemental=*/false},
+    {"atand", &I::genAtand},
     {"bessel_jn",
      &I::genBesselJn,
      {{{"n1", asValue}, {"n2", asValue}, {"x", asValue}}},
@@ -2313,6 +2318,22 @@
   return readAndAddCleanUp(resultMutableBox, resultType, "ANY");
 }
 
+mlir::Value IntrinsicLibrary::genAtand(mlir::Type resultType,
+                                       llvm::ArrayRef<mlir::Value> args) {
+  assert(args.size() == 1);
+  mlir::MLIRContext *context = builder.getContext();
+  mlir::FunctionType ftype =
+      mlir::FunctionType::get(context, {resultType}, {args[0].getType()});
+  mlir::Value atan = getRuntimeCallGenerator("atan", ftype)(builder, loc, args);
+  llvm::APFloat lpi = llvm::APFloat(llvm::numbers::pi);
+  mlir::Value dpi =
+      builder.createRealConstant(loc, mlir::FloatType::getF64(context), lpi);
+  mlir::Value pi = builder.createConvert(loc, resultType, dpi);
+  mlir::Value factor = builder.create<mlir::arith::DivFOp>(
+      loc, builder.createRealConstant(loc, resultType, 180), pi);
+  return builder.create<mlir::arith::MulFOp>(loc, atan, factor);
+}
+
 // ASSOCIATED
 fir::ExtendedValue
 IntrinsicLibrary::genAssociated(mlir::Type resultType,
diff --git a/flang/test/Lower/Intrinsics/atand.f90 b/flang/test/Lower/Intrinsics/atand.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/atand.f90
@@ -0,0 +1,30 @@
+! RUN: bbc -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-FAST"
+! RUN: bbc --math-runtime=precise -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-PRECISE"
+! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-FAST"
+
+function test_real4(x)
+  real :: x, test_real4
+  test_real4 = atand(x)
+end function
+
+! CHECK-LABEL: @_QPtest_real4
+! CHECK-PRECISE: %[[atan:.*]] = fir.call @atanf({{%[A-Za-z0-9._]+}}) {{.*}}: (f32) -> f32
+! CHECK-FAST: %[[atan:.*]] = math.atan %{{.*}} {{.*}} : f32
+! CHECK: %[[dpi:.*]] = arith.constant 3.1415926535897931 : f64
+! CHECK: %[[pi:.*]] = fir.convert %[[dpi]] : (f64) -> f32
+! CHECK: %[[deg:.*]] = arith.constant 1.800000e+02 : f32
+! CHECK: %[[factor:.*]] = arith.divf %[[deg]], %[[pi]] {{.*}} : f32
+! CHECK: %{{.*}} = arith.mulf %[[atan]], %[[factor]] {{.*}} : f32
+
+function test_real8(x)
+  real(8) :: x, test_real8
+  test_real8 = atand(x)
+end function
+
+! CHECK-LABEL: @_QPtest_real8
+! CHECK-PRECISE: %[[atan:.*]] = fir.call @atan({{%[A-Za-z0-9._]+}}) {{.*}}: (f64) -> f64
+! CHECK-FAST: %[[atan:.*]] = math.atan %{{.*}} {{.*}} : f64
+! CHECK: %[[pi:.*]] = arith.constant 3.1415926535897931 : f64
+! CHECK: %[[deg:.*]] = arith.constant 1.800000e+02 : f64
+! CHECK: %[[factor:.*]] = arith.divf %[[deg]], %[[pi]] {{.*}} : f64
+! CHECK: %{{.*}} = arith.mulf %[[atan]], %[[factor]] {{.*}} : f64