Children of kindergarten age develop very quickly. With proper stimuli, they should reach the appropriate level of school readiness around the age of six. The subject of the study carried out in one of Cracow’s kindergartens was to determine the level of school readiness in terms of social development. Tests were carried out among five-year-olds attending a kindergarten based on the pedagogic principles of Maria Montessori. The author wished to know what social skills were developed by the children within the context of an alternative method of interaction. The test group included 22 children from four mixed-age groups. The school readiness evaluation was carried out twice in the school year 2012/13, with the use of the categorised observation technique. The results show that within one year’s time of preparation for school the children made significant progress, but – due to their age and biological development – not all the required skills were shaped at the highest possible level. In the second test only 13.6% children obtained the highest grade in all the test indicators. More than 78% children obtained the high or medium level, which means that the skills tested have not been fully shaped. Children need more time for improving and reinforcing these skills. Social and emotional development is strictly related to the process of growing up. Therefore, certain skills cannot be shaped faster. These include an adequate reaction to new situations, overcoming difficulties, as well as performing and planning tasks on one’s own. The test results confirm that the Montessori educational context faclitates the shaping of such skills as independence of action, making good contacts with adults and peers, or preparing and tidying up the workplace. It was a partial and pilot study.