Objective　This　study　was　performed　to　examine　the　working　memory　(WM)　encoding　and　retrieval　abilities　in　patients　with　major　depressive　disorder　(MDD)　and　determine　whether　a　mood-congruent　memory　effect　is　present.　Methods　The　modified　Sternberg　WM　paradigm　with　positive,　negative,　and　neutral　emotional　pictures　was　used　to　investigate　the　WM　abilities　of　26　patients　with　MDD　and　26　healthy　controls　(HCs).　Results　No　significant　difference　in　picture　WM　was　found　between　the　MDD　and　HC　groups;　however,　the　accuracy　of　picture　position　WM　was　significantly　lower　and　the　response　time　was　significantly　longer　in　the　MDD　than　HC　group,　regardless　of　the　picture　or　position　WM.　Additionally,　in　the　MDD　group,　the　accuracy　of　negative　picture/position　WM　was　significantly　higher　than　that　of　positive　picture/position　WM.　Conclusions　These　results　suggest　that　in　patients　with　MDD,　spatial　WM　impairment　was　more　severe　than　object　WM.　In　addition,　these　patients＇　WM　retrieval　was　impaired,　resulting　in　a　decrease　in　WM　retrieval　ability,　which　may　be　an　important　cause　of　the　slow　thought　in　patients　with　MDD.　Moreover,　patients　with　depression　have　a　mood-congruent　memory　effect,　which　may　be　an　important　factor　in　the　occurrence　and　maintenance　of　depression.