Objective. This study assessed the association between self-ratings and key-worker ratings of depression in people with mild learning disabilities. Method. The Zung Depression Scale was completed by 74 adults with mild learning disabilities and a modified version of the questionnaire was completed by two key-workers at two periods in time. Results. The correlations between ratings of depression by key-workers were high and key-worker ratings correlated significantly with self-rating. The depression scores were found to be temporally stable. Conclusions. The findings suggest that proxy raters appear to be able to make reliable and valid judgements about other people's self-reported levels of depression.