diff --git a/rpc/client.go b/rpc/client.go
index f371ff7..2cf8656 100644
--- a/rpc/client.go
+++ b/rpc/client.go
@@ -86,13 +86,13 @@ func (c *Client) GetRecentBlockhash(ctx context.Context, commitment CommitmentTy
 }
 
 // GetSlot returns the current slot the node is processing.
-func (c *Client) GetSlot(ctx context.Context, commitment CommitmentType) (out GetSlotResult, err error) {
+func (c *Client) GetSlot(ctx context.Context, commitment CommitmentType) (out bin.Uint64, err error) {
 	var params []interface{}
 	if commitment != "" {
-		params = append(params, string(commitment))
+		params = append(params, M{"commitment": commitment})
 	}
 
-	err = c.rpcClient.CallFor(&out, "getSlot", params...)
+	err = c.rpcClient.CallFor(&out, "getSlot", params)
 	return
 }
 
diff --git a/rpc/types.go b/rpc/types.go
index 28bddf0..2e2b6a6 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -32,8 +32,6 @@ type GetBalanceResult struct {
 	Value bin.Uint64 `json:"value"`
 }
 
-type GetSlotResult bin.Uint64
-
 type GetRecentBlockhashResult struct {
 	RPCContext
 	Value BlockhashResult `json:"value"`