diff --git a/internal/sysinfo/memtotal_openbsd_amd64.go b/internal/sysinfo/memtotal_openbsd_amd64.go
new file mode 100644
index 000000000..2dc20960d
--- /dev/null
+++ b/internal/sysinfo/memtotal_openbsd_amd64.go
@@ -0,0 +1,35 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package sysinfo
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// PhysicalMemoryBytes returns the total amount of host memory.
+func PhysicalMemoryBytes() (uint64, error) {
+	mib := []int32{6 /* CTL_HW */, 19 /* HW_PHYSMEM64 */}
+
+	buf := make([]byte, 8)
+	bufLen := uintptr(8)
+
+	_, _, e1 := syscall.Syscall6(syscall.SYS___SYSCTL,
+		uintptr(unsafe.Pointer(&mib[0])), uintptr(len(mib)),
+		uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&bufLen)),
+		uintptr(0), uintptr(0))
+
+	if e1 != 0 {
+		return 0, e1
+	}
+
+	switch bufLen {
+	case 4:
+		return uint64(*(*uint32)(unsafe.Pointer(&buf[0]))), nil
+	case 8:
+		return *(*uint64)(unsafe.Pointer(&buf[0])), nil
+	default:
+		return 0, syscall.EIO
+	}
+}
diff --git a/internal/sysinfo/memtotal_openbsd_test.go b/internal/sysinfo/memtotal_openbsd_test.go
new file mode 100644
index 000000000..e12140848
--- /dev/null
+++ b/internal/sysinfo/memtotal_openbsd_test.go
@@ -0,0 +1,49 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package sysinfo
+
+import (
+	"errors"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"testing"
+)
+
+var re = regexp.MustCompile(`hw\.physmem=(\d+)`)
+
+func openbsdSysctlMemoryBytes() (uint64, error) {
+	out, err := exec.Command("/sbin/sysctl", "hw.physmem").Output()
+	if err != nil {
+		return 0, err
+	}
+
+	match := re.FindSubmatch(out)
+	if match == nil {
+		return 0, errors.New("memory size not found in sysctl output")
+	}
+
+	bts, err := strconv.ParseUint(string(match[1]), 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return bts, nil
+}
+
+func TestPhysicalMemoryBytes(t *testing.T) {
+	mem, err := PhysicalMemoryBytes()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mem2, err := openbsdSysctlMemoryBytes()
+	if nil != err {
+		t.Fatal(err)
+	}
+
+	if mem != mem2 {
+		t.Errorf("Expected %d, got %d\n", mem2, mem)
+	}
+}
diff --git a/v3/internal/sysinfo/memtotal_openbsd_amd64.go b/v3/internal/sysinfo/memtotal_openbsd_amd64.go
new file mode 100644
index 000000000..2dc20960d
--- /dev/null
+++ b/v3/internal/sysinfo/memtotal_openbsd_amd64.go
@@ -0,0 +1,35 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package sysinfo
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// PhysicalMemoryBytes returns the total amount of host memory.
+func PhysicalMemoryBytes() (uint64, error) {
+	mib := []int32{6 /* CTL_HW */, 19 /* HW_PHYSMEM64 */}
+
+	buf := make([]byte, 8)
+	bufLen := uintptr(8)
+
+	_, _, e1 := syscall.Syscall6(syscall.SYS___SYSCTL,
+		uintptr(unsafe.Pointer(&mib[0])), uintptr(len(mib)),
+		uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&bufLen)),
+		uintptr(0), uintptr(0))
+
+	if e1 != 0 {
+		return 0, e1
+	}
+
+	switch bufLen {
+	case 4:
+		return uint64(*(*uint32)(unsafe.Pointer(&buf[0]))), nil
+	case 8:
+		return *(*uint64)(unsafe.Pointer(&buf[0])), nil
+	default:
+		return 0, syscall.EIO
+	}
+}
diff --git a/v3/internal/sysinfo/memtotal_openbsd_test.go b/v3/internal/sysinfo/memtotal_openbsd_test.go
new file mode 100644
index 000000000..e12140848
--- /dev/null
+++ b/v3/internal/sysinfo/memtotal_openbsd_test.go
@@ -0,0 +1,49 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package sysinfo
+
+import (
+	"errors"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"testing"
+)
+
+var re = regexp.MustCompile(`hw\.physmem=(\d+)`)
+
+func openbsdSysctlMemoryBytes() (uint64, error) {
+	out, err := exec.Command("/sbin/sysctl", "hw.physmem").Output()
+	if err != nil {
+		return 0, err
+	}
+
+	match := re.FindSubmatch(out)
+	if match == nil {
+		return 0, errors.New("memory size not found in sysctl output")
+	}
+
+	bts, err := strconv.ParseUint(string(match[1]), 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return bts, nil
+}
+
+func TestPhysicalMemoryBytes(t *testing.T) {
+	mem, err := PhysicalMemoryBytes()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mem2, err := openbsdSysctlMemoryBytes()
+	if nil != err {
+		t.Fatal(err)
+	}
+
+	if mem != mem2 {
+		t.Errorf("Expected %d, got %d\n", mem2, mem)
+	}
+}