Introduction: Recent theories in cognitive psychology suggest that working memory (WM) processing involves a set of specific functions, in particular the WM functions of maintenance and interference control. Previous findings on WM impairments in patients with major depressive disorder (MDD) had been inconsistent, partly because earlier studies did not take into account these two different functions of WM. Method: Forty-two participants with MDD and 39 controls completed the visuospatial change detection task. We estimated the WM function of maintenance, based on performance in trials using the targets only, and the WM function of interference control, based on performance in trials with distractor rectangles. Results: Our results showed that participants with MDD had poorer WM function of maintenance and interference control than controls. However, the results of filtering efficiency did not show significant group difference, thus patients with MDD showed comparable impairments in WM function of maintanance as well as in WM function of interference control. Conclusion: Our findings suggested that patients with MDD appear to show generalised impairments on visuospatial WM function of maintenance and interference control. Future studies should use refined paradigms to assess the different functions of WM and their distinctive contributions to symptomatology of depression.