An effect of the Czech nature conservation law on a conservation status of bird species was examined using data on population size from two Atlases of breeding bird distribution in the Czech Republic (1985–1989 and 2001–2003). On average, species with the highest level of legal protection did better than other species. This pattern was probably driven by marked population increase of the species which were already increasing before the law came into the effect. Negative trends of declining species were not reversed after the law was accepted and it appears that the law failed to protect common bird species. Positive trends of protected species in the Czech Republic seem to mimic the trends in Europe and in neighbouring countries. Available official assessment of species conservation actions together with mixed message of our analysis suggest that the law could bring more positive results if implemented properly.