[eng] In biomedical research the biostatistics knowledge is fundamental to carry out the analysis of data obtained in research projects. However, health professionals usually show poor skills in this matter. This study aimed to evaluate the effectiveness of an intervention course about biostatistics in the knowledge and attitudes towards biostatistics of health residents. A quasi-experimental study was developed with an intervention consisted in a two-module course (introductory and advanced) with a participatory methodology, and practical activities with real examples of routine clinical practice and the use of computer tools to perform statistical analysis and mentoring help. To assess knowledge it was used the version translated into Spanish of the questionnaire Novack et al. and to determine attitudes it was applied the Survey of attitudes towards statistics questionnaire (SATS-28). The median in knowledge about biostatistics [11], test has significantly increased 3 points (Mann-Whitney U = 344.5; p<0.001) after completing the course. The attitude scale (SATS-28) has also increased positively by 1.64 points (Mann-Whitney U= 355, p=0.0002), highlighting the greater increase in the cognitive competence subscale with 2.67 points (U Mann-Whitney = 232.5, p<0.0001). A significant positive correlation was found between the global score of the knowledge and attitude (pre-course: p<0.001, Rho= 0.79; post-course: p-value<0.001, Rho=0.62). The use of participatory educational strategies by promoting the management of statistical programs in combination with real cases and mentoring improve the attitude and the knowledge of biostatistics in health residents.