Automatic processes require few attentional resources, but effortful processes use attentional capacity. Research on cognitive processing by depressed individuals is reviewed and the following is concluded: (a) Depression interferes with effortful processing. The degree of interference is determined by the degree of effortfulness of the task, the severity of depression, and the valence of the stimulus material to be processed. (b) Depression interferes only minimally with automatic processes. Hypothetical causal mechanisms for interference in effortful processes by depression, whether interference in effortful processing is unique to depression or characteristic of psychopathology in general, and whether negative automatic thoughts are associated with current depression or depression proneness are also addressed. The effortful-automatic perspective has implications for understanding depressive clinical features, treating depression, and conducting future research.