Background: Proficiency in placing infraclavicular subclavian venous catheters can be achieved through practice and repetition. But few data specifically document insertion technical errors, which mentors could teach novice operators to avoid. Study Design: Surgical, medical, and anesthesia textbooks and procedural handbooks were reviewed. Subclavian catheter placement technical errors described were identified and consolidated. Video captures from 86 consecutive patients receiving subclavian central venous catheterizations at an urban trauma center were evaluated. In each video segment, the number of attempts at insertion, the number of failures at insertion, and the technical error observed during failed attempts were recorded and tabulated. Results: Of the 86 subclavian line placements attempted, 77 were successful (89.5%), with a total of 357 subclavian venipuncture attempts and 279 failures (78% attempt failure rate). There was a mean of 3.2 failed attempts per line (left side, 2.1 attempts; right side, 5.5 attempts). Junior residents (PGY 1 to 2) had more failures per line than senior residents (PGY 3 to 5): 4.1 versus 3.6. The most common technical errors observed were improper site for needle insertion relative to the clavicle; insertion of the needle through the clavicular periosteum; too shallow of a trajectory for the needle; improper or inadequate anatomic landmark identification; aiming the needle too cephalad; and inadvertent movement of the needle out of the vein before or during wire placement. Conclusions: In subclavian central venous access attempts, there are six common technical errors. Mentors can improve novice operators' proficiency by teaching them to avoid these errors.