The invention relates to glucocorticoid replacement therapy and provides pharmaceutical compositions and kits designed to deliver one or more glucocorticoids to a subject in need thereon in a manner that results in serum levels of the glucocorticoid that essentially mimic that of a healthy subject for a clinically relevant period of time. The pharmaceutical compositions and kits are prepared in such a way that a first part of one or more glucocorticoids is substantially immediately released and a second part of one or more glucocorticoids is released over an extended period of time of at least about 8 hours. The invention also relates to a method for treating diseases requiring glucocorticoid treatment such as in subjects having a glucocorticoid deficiency disorder.