BACKGROUND: Studies from different countries have reported an increased incidence of primary cutaneous lymphomas over the last decades. OBJECTIVES: To estimate the incidence rates of primary cutaneous T-cell lymphoma (CTCL) and mycosis fungoides (MF)/Sézary syndrome (SS) in Norway, and to compare these rates with those reported from other countries. METHODS: Data from the Cancer Registry of Norway on non-Hodgkin lymphomas during the period 1980-2003 were analysed. RESULTS: In total, 337 cases of CTCL were reported to the Cancer Registry during the study period, of which 262 cases were classified as MF/SS. The incidence rate of CTCL increased significantly (P(trend)