Nonmelanoma skin cancer (NMSC) is the most common cancer among Caucasian populations worldwide, and incidence rates are increasing. However, NMSC data are not routinely collected by cancer registries, but Denmark has extensive registration of NMSC in two nationwide population-based registries. We assessed incidence trends of NMSC in Denmark from 1978 to 2007. Data for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were obtained from the Danish Cancer Registry and the Danish Registry of Pathology. For both genders, age-specific incidence rates and overall incidence rates, age-adjusted according to the World standard population were calculated based on combined data from the two registries. For both genders, a high increase in both BCC and SCC incidence was observed over time. Between 1978 and 2007, the age-adjusted BCC incidence increased from 27.1 to 96.6 cases per 100,000 person-years for women and from 34.2 to 91.2 cases for men. The SCC incidence increased from 4.6 to 12.0 cases per 100,000 person-years for women and from 9.7 to 19.1 cases for men. For both BCC and SCC, women experienced a higher average annual percentage incidence change than men. Furthermore, the average annual percentage change in BCC incidence among persons below 40 years was significantly higher compared to older persons, especially for women. These trends may lead to an alarming NMSC incidence increase over time as population ages and will have major implications for future healthcare services. Our findings underline the need for improved preventive strategies to hamper the increasing NMSC incidence.