A multiple lumen catheter (110,150) having at least first and second lumens (112,114 152,154). At least one of the first and second lumens (112,152) is generally C-shaped in cross-section, with a septum wall (120,160) dividing the first and second lumens providing a generally straight side to the C-shaped cross-section. A stylet or guide wire (130) may be disposed along the C-shaped cross-section lumen (112,152,154) having a larger diameter than one used with catheters of the same outer diameter but that have lumens of only D-shaped or circular shaped cross-sections.
