We report the first-ever prevalence study of selective mutism in Poland. Preschool and primary school teachers were surveyed at four locations; parents were followed up if selective mutism was suspected. Our point prevalence rate of selective mutism (per thousand children) was 5.7 for 3-6 years-old preschoolers (95% confidence interval: 3.7-8.8); 2.0 (1.1-3.9) for 1st-3rd graders; and 2.1 (0.9-5.1) for 4th-6th graders. The accuracy of that estimate may be compromised by low response rate. 56% were girls. Less than 20% had been formally diagnosed with the condition, which suggests lack of adequate recognition and support.