This paper examines the production and reduction of sea ice area in the Sea of Okhotsk. Analyses were carried out for 10 winters (December--April) from 1991/1992 to 2000/2001 using daily data of sea ice velocity and concentration, derived from images of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I). First, we mapped sea ice divergence, which was calculated from the daily ice velocity field. In the case of offshore winds, high divergence was observed along the coastline, while there existed a broad convergence area with inshore winds. Next, we examined local changes in an area of sea ice. As in the case of ice divergence, ice production and reduction are strongly controlled by wind direction. We found that a large amount of sea ice was produced in coastal areas under offshore wind conditions. The geographical distribution of the ice production area agrees well with that of the well-known coastal polynya areas. Our estimation shows that 8.7 ¿ 105 km2 yr-1 of sea ice is produced in the northern coastal area, and 3.7 ¿ 105 km2 yr-1 in the Sakhalin coastal area. In contrast, 7.4 ¿ 105 km2 yr-1 of the ice area disappeared in Shantarskiy Bay. This reduction of ice area is mainly caused by dynamic deformation of existing ice forming rafted ice or pressure ridges. This dynamic deformation plays an important role, not only in the reduction of Okhotsk sea ice area, but also in the thickening of ice.