This paper analyzes the effects of regular seasonal fluctuations of macroeconomic variables in Turkey due to the religious events (religious holidays and Ramadan)[1] in monthly frequency. Conventional deterministic deseasonalization techniques are applied to the detrended and linearized major macroeconomic series. Investigation of the seasonally filtered series reveals residual seasonal regularities vis-à-vis the religious holidays and Ramadan  for some of the series. Consequences of ignoring this type of seasonality are also scrutinized.