diff --git a/cast.go b/cast.go
index 28ee04a..094b748 100755
--- a/cast.go
+++ b/cast.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/cep21/circuit/v3"
 	"github.com/cep21/circuit/v3/closers/hystrix"
+	"github.com/opentracing/opentracing-go"
 
 	"github.com/sirupsen/logrus"
 )
@@ -123,6 +124,16 @@ func (c *Cast) Do(ctx context.Context, request *Request) (*Response, error) {
 		}
 	}
 
+	tracer := opentracing.GlobalTracer()
+	span := opentracing.SpanFromContext(ctx)
+	if tracer != nil && span != nil {
+		err := tracer.Inject(span.Context(), opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(request.header))
+		if err != nil {
+			c.logger.WithError(err).Error("tracer.Inject")
+			return nil, err
+		}
+	}
+
 	request.rawRequest, err = http.NewRequestWithContext(ctx, request.method, c.baseURL+request.path, bytes.NewReader(body))
 	if err != nil {
 		c.logger.WithError(err).Error("http.NewRequest")
diff --git a/go.mod b/go.mod
index 2d8fca9..4f4b83d 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ require (
 	github.com/google/go-querystring v1.0.0
 	github.com/jtacoma/uritemplates v1.0.0
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
+	github.com/opentracing/opentracing-go v1.2.0
 	github.com/sirupsen/logrus v1.4.2
 	golang.org/x/sys v0.0.0-20191029155521-f43be2a4598c // indirect
 )
diff --git a/go.sum b/go.sum
index 2b176c2..c605cd6 100644
--- a/go.sum
+++ b/go.sum
@@ -18,6 +18,8 @@ github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfV
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2 h1:DB17ag19krx9CFsz4o3enTrPXyIXCl+2iCXH/aMAp9s=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
+github.com/opentracing/opentracing-go v1.2.0 h1:uEJPy/1a5RIPAJ0Ov+OIO8OxWu77jEv+1B0VhjKrZUs=
+github.com/opentracing/opentracing-go v1.2.0/go.mod h1:GxEUsuufX4nBwe+T+Wl9TAgYrxe9dPLANfrWvHYVTgc=
 github.com/peterbourgon/g2s v0.0.0-20170223122336-d4e7ad98afea/go.mod h1:1VcHEd3ro4QMoHfiNl/j7Jkln9+KQuorp0PItHMJYNg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=