Spring evaluation of three sampling methods to estimate family richness and abundance of arthropods in olive groves.-The intensification and expansion of agriculture is currently one of the greatest threats to biodiversity worldwide. Olive groves are one of the most extensive and diverse agroecosystems in the Mediterranean region. However, the efficiency of the methods used to sample arthropods in olive crops remains unclear. We compared the effectiveness of pan traps, sweep net and bait traps used to sample arthropods in olive groves. The pan traps collected 19 orders and 182 families, with an abundance that was 76% and 86% higher than that of sweep nets and bait traps, respectively. The composition of families differed significantly according to the method used; from a total of 234 families, 23% were sampled only by pan traps, 16% only by sweep net and 5% only by bait traps. The sampling method was the best predictor of arthropod abundance and number of families, followed by the vegetation and landscape diversity indexes. As pan trap, sweep net and bait trap methods do not obtain the same results when sampling arthropods, we recommend a combination of pan traps and a sweep net, depending on the goal of the studies and the arthropod groups targeted.