Objective. To evaluate the effects of local application of ice chips, ligno-paraffin, short-wave diathermy, and nitrogen-cold air on skin and intraarticular temperature. Methods. Forty-two healthy subjects were divided into 4 treatment groups. A temperature probe was inserted into the knee joint cavity and another placed on the overlying skin, and changes in temperature over 3 hours, by treatment group, were recorded. Results. The mean skin surface temperature dropped from 27.9°C to 11.5°C after application of ice chips, and from 28.8°C to 13.8°C after application of cold air. The mean intraarticular temperature decreased from 31.9°C to 22.5°C and from 32.9°C to 28.8°C, respectively, after these 2 treatments. Short-wave diathermy increased skin temperature by 2.4°C; intraarticular temperature was increased only 1.4°C by short-wave diathermy. Treatment with ligno-paraffin increased the skin surface temperature 8.9°C; the temperature in the joint cavity was increased 3.5°C. Conclusion. The use of short-wave diathermy and superficial heat packs in the treatment of patients with arthritis may potentially cause harm by increasing intraarticular temperature. This may have major implications regarding treatment policy for patients with arthritis.