This chapter addresses the importance of accuracy and precision in anthropometric measurements, highlighting how measurement errors can affect the interpretation of results. Various sources of error are mentioned, including challenges related to the measurement technique, environmental conditions, the biological variability of individuals, the verification of the equipment used, and the reading and recording of data. The need to follow standardised protocols to minimise error is emphasised, as well as the importance of training and familiarisation with the equipment used. In addition, specific recommendations are provided to reduce measurement errors, such as taking multiple measurements of the same variable and maintaining a suitable environment for measurements. The second part of the chapter specifies how to perform the error analysis in anthropometry. Thus, it delves into the concepts of precision (intra-evaluator technical measurement error), validity, accuracy (inter-evaluator technical measurement error) and probability of success (confidence intervals), as well as the calculations for each of them and the interpretation of the results.