The therapy of first choice for treating Seasonal Affective Disorder, winter type, is light treatment. Meta analyses have shown that light therapy in the morning has the highest chance to be successful. In the Netherlands, common practice is 30-45 minutes of bright light therapy in the morning for five consecutive days. If given early in the development of depressive symptoms, one week of light therapy is in most cases enough to treat the depression and stay well during the remainder of the winter. In this retrospective study we analyzed whether early types respond better to the treatment at 8 am in the morning than late types. This was not the case; no significant relationship was found between chronotype, as measured with the morningness-eveningness questionnaire and therapy success with LT as a fixed timepoint. This questions whether the mechanism behind the effect has anything to do with a phase shift of the biological clock