We conducted visual surveys of the red squirrel Sciurus vulgaris in 2005 in 11 parks and city forests of Warsaw with particular focus on the population in Łazienki Park in the city center. We found a significant association between the size of the park and the number of observed red squirrels, with the highest number occurring in Łazienki Park. In this park, the abundance index of the population in 2005 was 1.8 individuals per ha, which was three times higher than in 1956 and 1986, when similar surveys were carried out. The number of red squirrels observed in Łazienki Park was influenced by season, temperature, air humidity and tree species, the seeds of which are a potential food source for red squirrels.