The study discusses the issue of assessment of investment projects planned in environmentally valuable areas. The study area was Biebrza National Park. The source of data was the available literature on the subject, as well as information contained in the Chronicles of Biebrza National Park of year 2015 and 2016. An interview with the park authorities was also conducted. Analyses were developed and conclusions were drawn with regard to investments in the park area. The types of investment projects implemented were specified, as well as the share of these projects in communes located within the park area in relation to the number of inhabitants. It was found that investment projects implemented in the areas protected as a part of the national park were investments in farm buildings, animal houses and – most of all – residential buildings.