1. Stable isotope analysis (SIA) is widely used in ecology, but samples are usually analysed in specialist facilities. Like any complex process, SIA is susceptible to human error. Despite the best efforts of the SIA laboratory, errors may occasionally remain in results released to clients. 2. We used our experiences as ecologists and laboratory analysts to identify human error scenarios to which SIA performed anywhere might be susceptible. These scenarios ran from sample selection and submission by the ecologist, to the final results report from the SIA laboratory. Several scenarios involved errors hard to find by visual examination, by either ecologist or analyst. 3. The ecologist can prevent pre-submission errors by formalising their sample submission process, and can best perform a final results quality check by submitting their own quality control material with a matrix similar to that of the samples. Prevention of laboratory errors is best accomplished by a comprehensive quality management system and a continual-improvement, no-blame laboratory culture. 4. We recommend that the ecologist views the entire sample selection, submission, and laboratory analysis as an integrated whole, establishing their own quality management processes to run alongside those of the SIA facility. This recommendation applies to any ecological methodology where samples are sent to a specialist facility for analysis.