A major goal of today's biology is to understand the genetic basis of quantitative traits. This can be achieved by statistical methods that evaluate the association between molecular marker variation and phenotypic variation in different types of mapping populations. The objective of this work was to evaluate the statistical power of QTL detection of various multi-parental mating designs as well as to assess the reasons for the observed differences. Our study was based on empirical data of 20 Arabidopsis thaliana accessions which have been selected to capture the maximum genetic diversity. The examined mating designs differed strongly with respect to the statistical power to detect QTL. We observed the highest power to detect QTL for the diallel cross with random mating design. The results of our study suggested that performing sibling mating within subpopulations of joint linkage mapping populations has the potential to considerably increase the power for QTL detec tion. Our results, however, revealed that using designs in which more than two parental alleles segregate in each subpopulation increases the power even more.