There is a lack of consensus of the frequency of follow-up of laboratory parameters during isotretinoin treatment. We conducted a retrospective analysis of the changes in laboratory parameters used in daily practice for patients with acne who were treated with isotretinoin to determine the optimum test repetition frequency. Patient demographic data; cumulative isotretinoin doses; alanin transaminase (ALT), aspartate transaminase (AST), γ-glutamyltransferase (GGT), creatinine kinase (CK), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels during treatment were recorded. Our findings support the idea that routine monthly monitoring of normal laboratory parameters is unnecessary and wasteful. Periodic monitoring of abnormal laboratory parameters should be considered on an individual basis.