Urine testing has increasingly become one of the methods used in the attempt to reduce misuse in Swedish prisons. A considerable increase in the number of urine analyses conducted occurred between August 1981 and September 1982, primarily at the local institutions. The analyses were for amphetamines, opiates, and cannabis. A total of 16,270 analyses were conducted on samples sent from 62 national and local prisons. Three additional national prisons (Hinseberg, Harlanda, and Osteraker) produced a total of 35,750 analyses, 68 percent of all prison urine analyses for the period. For the 16,720 urine analyses, positive results for amphetamines and opiates were 265 and 93 respectively. A total of 1,556 cannabis analyses were positive. Thirteen percent of the prisons accounted for 52 percent of the positive cannabis analyses. Of the 35,750 analyses from the three national prisons, 98 amphetamine analyses and 70 opiate analyses were positive. A total of 718 of the cannabis analyses were positive. Overall, for the national prisons, 98 percent of amphetamine analyses and 99 percent of opiate analyses were negative, while 78 percent of cannabis analyses were negative. Local institutions had negative findings for 94 percent of amphetamine analyses and 98 percent of opiate analyses; 68 percent of cannabis analyses were negative. Costs for the various types of drug analyses are provided, along with other tabular data.