Objective: To review the feasibility and effectiveness of single daily dosing of lithium in patients with affective disorder and to discuss advantages and disadvantages of this schedule of administration. Method: A comprehensive search of the literature was conducted using a combination of electronic databases and a search of reference lists and relevant journals. English-language articles were selected for the review if they discussed the issues comparing multiple and single daily dosing schedules of lithium. Results: We found 9 comparative studies. Single daily dosing of lithium causes transient higher peak lithium concentrations; however, no comparative study revealed a significant difference in side effects between multiple and single daily dosing groups. Numerous reports concluded that taking lithium in a single dose prevents, or at least limits, the increase in urine output (and the reduction of osmolality) and subsequent thirst. There is no evidence that a single lithium dosing schedule preserves glomerular function. Conclusion: According to the presented data, it could be reasonable to use lithium as a single evening dose in patients who can tolerate this schedule because no studies have suggested any benefit from administration of multiple daily doses. Possible advantages of single daily dosing, especially in improved compliance, could not be veiled by disadvantages of transient and mild postabsorptive side effects.