Meta-analysis was used to synthesize findings from comparative studies of depression in mothers of children with and without developmental disabilities. Effect sizes were determined for 18 studies conducted between 1984 and 2003. A weighted effect size of .39 indicated an elevated level of depression in mothers of children with developmental disabilities. Planned comparisons found that age of child and disability category moderated effect sizes. Results show that mothers of children with developmental disabilities are at elevated risk of depression compared to mothers of typically developing children. Depression in mothers of children with developmental disabilities is a condition that is presently not being addressed on a wide scale, although promising interventions are available.