Background. Complications of spinal anaesthesia (SpA) range between 1 and 17%. Habitus and operator experience may play a pivotal role, but only sparse data is available to substantiate this claim. Methods. 161 patients were prospectively enrolled. Data such as spread of block, duration of puncture, number of trials, any complication, operator experience, haemodynamic parameters, was recorded and anatomical patient habitus assessed. Results. Data from 154 patients were analyzed. Success rate of SpA in the group of young trainees was 72% versus 100% in the group of consultants. Trainees succeeded in patients with a normal habitus in 83.3% of cases versus 41.3% when patients had a difficult anatomy (P = 0.02). SpA in obese patients (BMI ≥ 32) was associated with a significantly longer duration of puncture, an increased failure ratio when performed by trainees (almost 50%), and an increased number of bloody punctures. Discussion. Habitus plays a pivotal role for SpA efficiency. In patients with obscured landmarks, failure ratio in unexperienced operators is high. Hence, patient prescreening as well as adequate choice of operators may be beneficial for the success rate of SpA and contribute to less complications and better patient and trainee satisfaction.