The psychometric properties of Scheier and Carver's 1985 Life Orientation Test (LOT), which is a measure of optimism, were examined as part of a study of education, training, work experience, and expectations of sentenced adult prisoners in Western Australia. All prisoners at five metropolitan public prisons were invited to participate and 453 accepted. This represented a response rate overall of about 41%, with response rates at each of the individual prisons ranging from 13% to 90%. The average age of the prisoner sample was 34.4 yr. (SD = 10.2 yr.). The proportion of men in the sample was 79.7%. Mean sentence length was 66.9 mo. (58.5 for women and 69.2 for men), and the number of months of sentence remaining averaged 44.4 mo. (41.0 for women and 45.3 for men). Means and standard deviations of the LOT scores for prisoners were similar to those of other groups, and demographic differences between prisoners were not statistically significantly related to scores. The internal reliability of the LOT scores was acceptable. Confirmatory factor analyses indicated that the two-factor item-keying model fitted the prisoner data better than a one-factor model. However, the two factors did not simply reflect underlying optimism and pessimism constructs but were substantially affected by item keying.