The present invention provides further improved compositions and methods for efficient lysosomal targeting based on the GILT technology. Among other things, the present invention provides methods and compositions for targeting lysosomal enzymes to lysosomes using furin-resistant lysosomal targeting peptides. The present invention also provides methods and compositions for targeting lysosomal enzymes to lysosomes using a lysosomal targeting peptide that has reduced or diminished binding affinity for the insulin receptor.