A multi-lumen catheter (100) comprising: a tubular shaft member (110) having a proximal end, a distal end and a longitudinal length therebetween, the tubular shaft member having a first lumen (212) and a second lumen (214) defined therein, the first lumen having a first lumen cross-sectional dimension and a length extending at least along a portion of the length of the tubular shaft member, and the second lumen having a second lumen cross-sectional dimension and a length extending along the length of tubular shaft member, characterized in that the tubular shaft member is a monolithic elongate tubular shaft member having an inner core (210) made of a first material, an outer layer (220) made of a second material, and an intermediate tie layer disposed between the inner core and the outer layer, the first material of the inner core defining the first lumen and the second lumen therein, the first lumen cross-sectional dimension being substantially uniform along the length of the first lumen, the second lumen cross-sectional dimension being substantially uniform along the length of the second lumen, and the tubular shaft member having an outer cross-sectional dimension that varies along the length of the tubular shaft member.