The　rapid　detection　of　microcystin-leucine-arginine　(MC-LR),　the　most　highly　toxic　among　MCs,　is　significantly　important　to　environmental　and　human　health　protection　and　prevention　of　MC-LR　from　being　used　as　a　bioweapon.　Although　aptamers　offer　higher　affinity,　specificity,　and　stability　with　MC-LR　than　antibodies　in　the　immunodetection　of　MC-LR　due　to　steric　hindrance　between　two　antibodies　and　limited　epitopes　of　MC-LR　for　use　in　a　sandwich　immunoassay,　no　sandwich　immunoassay　using　an　aptmer　has　been　developed　for　MC-LR　detection.　This　study　is　aimed　at　developing　an　aptamer-antibody　immunoassay　(AAIA)　to　detect　MC-LR　using　a　portable　analyzer.　The　aptamers　were　immobilized　onto.　the　glass　surface　of　a　microchamber　to　capture　MC-LR.　MC-LR　and　horseradish　peroxidase　(HRP)-labeled　antibody　were　pulled　into　the　microchamber　to　react　with　the　immobilized　aptamer.　The　chemiluminescence　(CL)　catalyzed　by　HRP　was　tested　by　a　photodiode-based　portable　analyzer.　MC-LR　at　0.5-4.0　mu　g/L　was　detected　quantitatively　by　the　AAIA,　with　a　CL　signal　sensitivity　of　0.3　mu　g/L.　The　assay　took　less　than　35　min　for　a　single　sample　and　demonstrated　a　high　specificity,　detecting　only　MC-LR,　but　not　MC-LA,　MC-YR,　or　nodularin-R.　The　recovery　of　two　spiked　real　environmental　samples　calculated　as　94.5-112.7%.　Therefore,　this　AAIA　was　proved　to　be　a　rapid　and　simple　method　to　detect　MC-LR　in　the　field　by　a　single　analyst.　(C)　2014　Elsevier　B.V.　All　rights　reserved.