Aim. The presented suicide seasonality analysis based on the Main Statistical Office general Polish population data is the first to deal with this problem in our country. An answer was sought to two research questions: whether the phenomenon of suicide seasonality occurs in Poland, and if so, whether there are any age- and gender-related differences in the seasonality pattern. Moreover, the obtained results were compared with seasonality patterns reported in other countries. Method. Statistical analyses were performed using the Demetra v.2.04. programme. The total of 29,232 cases of suicidal death registered in Poland in the years 1999-2003 were analysed. Results. In the study, a stable seasonality of suicides was found in three groups: in the general Polish population, in the 40-44 age group irrespective of gender, and in males aged 40-44. A stable seasonality pattern was confirmed to exist in the period under study, with a peak in the spring-summer time and a clear decline in winter. No stable seasonality of suicide was found in women. Conclusions. The findings are concordant with a majority of these reported in studies of this type in other countries. The obtained results can be used in the future to assess changes in the suicide seasonality amplitude in Poland over time. Moreover, it seems worthwhile to corroborate the observation made by other authors that seasonality is modified mainly by violent suicides