The present invention provides a dialysis coupler assembly comprising a pair of rubber-like elastic tubular couplers, and a pair of joint members for joining the couplers together. Each of the couplers includes an inner channel 14 allowing a connector associated with a medical device to be fitted therein, and a smooth surface 15, 16 perpendicular to the longitudinal axis of the coupler. The couplers are adapted to be joined together through the joint members in such manner that the smooth surfaces are in liquid-tight contact with one another. Each of the joint members is adapted to be attached slidably and rotatably onto corresponding one of the couplers, the joint members having first and second engagement portions, respectively. The first and second engagement portions are disposed opposed to one another and adapted to cooperatively engage the joint members with one another so as to allow the smooth surfaces to be brought into liquid-tight contact with one another.