diff --git a/format/fit/fit.go b/format/fit/fit.go
new file mode 100644
index 0000000000..1ee4f77abf
--- /dev/null
+++ b/format/fit/fit.go
@@ -0,0 +1,147 @@
+package fit
+
+// https://developer.garmin.com/fit/protocol/
+import (
+	"sort"
+
+	"github.com/wader/fq/format"
+	"github.com/wader/fq/format/registry"
+	"github.com/wader/fq/pkg/decode"
+)
+
+type field_definition struct {
+	number    uint8
+	size      uint8
+	base_type struct {
+		endian_ability uint8
+		number         uint8
+	}
+}
+
+func init() {
+	registry.MustRegister(decode.Format{
+		Name:        format.FIT,
+		Description: "Flexible and Interoperable Data Transfer (FIT) Protocol",
+		DecodeFn:    decodeFIT,
+	})
+}
+
+func decodeFieldDefinition(d *decode.D) field_definition {
+	var field field_definition
+	field.number = uint8(d.FieldU8("field_definition_number"))
+	field.size = uint8(d.FieldU8("size"))
+	field.base_type.endian_ability = uint8(d.FieldU1("base_type_endian_ability"))
+	d.RawLen(2)
+	field.base_type.number = uint8(d.FieldU5("base_type_number"))
+	return field
+}
+
+func decodeDataMessage(d *decode.D, fields []field_definition) {
+	sort.Slice(fields, func(p, q int) bool {
+		return fields[p].number < fields[q].number
+	})
+
+	d.FieldArray("field", func(d *decode.D) {
+		for _, e := range fields {
+			switch e.base_type.number {
+			case 0:
+				if (e.size / 1) > 1 {
+					d.FieldArray("values", func(d *decode.D) {
+						array_size := e.size / 1
+						for i := uint8(0); i < array_size; i++ {
+							d.FieldU8("enum")
+						}
+					})
+				} else {
+					d.FieldU8("enum")
+				}
+			case 4:
+				if (e.size / 2) > 1 {
+					d.FieldArray("values", func(d *decode.D) {
+						array_size := e.size / 2
+						for i := uint8(0); i < array_size; i++ {
+							d.FieldU16("uint16")
+						}
+					})
+				} else {
+					d.FieldU16("uint16")
+				}
+			case 6:
+				if (e.size / 4) > 1 {
+					d.FieldArray("values", func(d *decode.D) {
+						array_size := e.size / 4
+						for i := uint8(0); i < array_size; i++ {
+							d.FieldU32("uint32")
+						}
+					})
+				} else {
+					d.FieldU16("uint32")
+				}
+			case 12:
+				if (e.size / 4) > 1 {
+					d.FieldArray("values", func(d *decode.D) {
+						array_size := e.size / 4
+						for i := uint8(0); i < array_size; i++ {
+							d.FieldU32("uint32z")
+						}
+					})
+				} else {
+					d.FieldU16("uint32z")
+				}
+			}
+		}
+	})
+}
+
+func decodeDefinitionMessage(d *decode.D) []field_definition {
+	d.FieldU8("reserved")
+	d.FieldU8("architecture")
+	d.FieldU16("global_message_number")
+	num_of_fields := d.FieldU8("fields")
+	var fields []field_definition
+	d.FieldArray("field_definitions", func(d *decode.D) {
+		for i := uint64(0); i < num_of_fields; i++ {
+			d.FieldStruct("field_definition", func(d *decode.D) {
+				fields = append(fields, decodeFieldDefinition(d))
+			})
+		}
+	})
+	return fields
+}
+
+func decodeFIT(d *decode.D, in interface{}) interface{} {
+	d.Endian = decode.LittleEndian
+	size := d.FieldU8("header_size")
+	if size < 12 {
+		d.Fatalf("Header size too small < 12")
+	}
+	d.FieldU8("protocol_version")
+	d.FieldU16("profile_version")
+	d.FieldU32("data_size")
+	d.FieldUTF8("data_type", 4, d.AssertStr(".FIT"))
+	d.FieldU16("crc")
+	d.FieldArray("records", func(d *decode.D) {
+		var fields []field_definition
+		for i := uint64(0); i < 4; i++ {
+			d.FieldStruct("record_header", func(d *decode.D) {
+				d.FieldU1("normal_header")
+				messge_type := d.FieldU1("message_type")
+				d.FieldU1("message_type_specific")
+				d.FieldU1("reserved")
+				d.FieldU4("local_message_type")
+
+				if messge_type == 1 {
+					fields = nil
+					d.FieldStruct("definition_message", func(d *decode.D) {
+						fields = append(fields, decodeDefinitionMessage(d)...)
+					})
+				} else {
+					d.FieldStruct("data_message", func(d *decode.D) {
+						decodeDataMessage(d, fields)
+					})
+				}
+			})
+		}
+	})
+	return nil
+}
diff --git a/format/fit/testdata/test.fit b/format/fit/testdata/test.fit
new file mode 100644
index 0000000000..09e0fd99f8
Binary files /dev/null and b/format/fit/testdata/test.fit differ