The present invention provides, among other things, compositions, kits and methods for subcutaneous delivery of lysosomal enzymes for effective treatment of lysosomal storage diseases. In some embodiments, the present invention provides methods for treating Hunter syndrome by subcutaneous administration of a replacement iduronate-2-sulfatase (I2S) protein. In some embodiments, the present invention provides a kit comprising an arrangement of components for subcutaneously administering iduronate-2-sulfatase (I2S) protein.