The effect of three different therapeutic regimens on bone mineral content at the radius and lumbar spine was studied in a group of 60 postmenopausal rheumatoid arthritis patients. Results were compared to those in a group of controls matched for sex, age, disease duration and menopausal state. Serum and urinary parameters of calcium metabolism were also evaluated in the three treatment groups. The three treatment regimens were: 1 alpha hydroxyvitamin D + calcium + placebo; 1 alpha hydroxyvitamin D + calcium + lynestrenol; and 1 alpha hydroxyvitamin D + calcium + sodium fluoride. In all treatment groups there was a positive effect of therapy compared to controls, though this was only significant in the 1 alpha hydroxyvitamin D + calcium + lynestrenol group at the axial skeleton after 1 and 2 years of treatment. Serum calcium rose significantly in the 1 alpha hydroxyvitamin D + calcium + placebo group and serum creatinin was raised in all the treatment groups during therapy. In the 1 alpha hydroxyvitamin D + calcium + lynestrenol group, serum alkaline phosphatase activity and urinary hydroxyproline excretion decreased significantly.