During the years 2004-2008 the distribution of the Common Adder and the Slow Worm were studied in Silesia through questionnaire directed to forest inspectorates (n=871); 83.8% of them responded. These data were tested through field work in several randomly selected inspectorates. Both species were found to be widespread in the region, with a few strongholds identified in Sudety Mts. and larger forest complexes. The Common Adder was recorded in 68.5% of forest districts which responded, while the Slow Worm – in 73.6% of those districts. Changes in distribution and population trends could not be derived, since no reliable data were available from previous years.