A chemically modified human Growth Hormone (rhGH) prepared by attaching a transient linker which comprises a polyethylene glycol. The chemically modified protein may have a much longer lasting rhGH activity than that of the unmodified rhGH, enabling reduced dose and scheduling opportunities and the modified rhGH may not cause lipoatrophy. Also includes methods of use for the treatment and/or prevention of diseases or disorders in which use of growth hormone is beneficial.