Background: Epidemiological studies have shown that short- and long-term exposure to ambient particulate air pollution is associated with adverse health effects. However, less is known if these patterns also justify in North-Eastern Europe. Aim: Current study aimed to assess if short-term exposure to particulate matter affects the mortality in Tallinn, capital of Estonia. Methods: Daily mortality caused by non-external causes (ICD-10 codes A to R) in Tallinn, was modelled between 2004 and 2011 as dependent on particular matter (PM) concentrations measured in residential area defined as urban background (particle sizes of 10 µm and 2.5 µm, denoted PM10 and PM2.5 respectively) with up to six previous days' concentration, as well as on air temperature, humidity, and season (based on compulsory winter, usually studded tyre period), using general additive models (GAM) with smoothers of time and air temperature. Due to the switch of measure tools in station, the PM variables were standardized. Results: In summer (Apr–Sept), we estimated 3.42% increase (95% CI 1.70–5.16) in daily mortality per 10-?g/m3 increase in PM10 in previous day (lag 1). In winter (Oct–Mar), we estimated 2.11% decrease (95% CI 0.04–4.31) in daily mortality per 10-?g/m3increase in PM10 in previous day. In a summer, 10 ?g/m3 rise of PM2.5 in previous day increases mortality by 5.25% (95% confidence interval: 1.98–8.61). In a winter 10 ?g/m3 rise of PM2.5 in previous day decreases mortality by 0.86% (95% CI -2.54–4.39). Conclusions: The study showed that days with higher concentration of both PM10 and PM2.5 increase the mortality in Tallinn in the following day during the summer; however, in winter no such trend appeared.