Outsourcing, its processes and efficiency, factors and barriers, risks and benefits are most frequently analysed for the conditions of private companies. However, outsourcing is also very frequent in the public sector, both on the level of public organizations and self-government. The goal of our chapter was to analyse the outsourcing of ancillary services on the Slovak municipal level. According to our findings, the scale of outsourcing ancillary services on the municipal level is relatively large (depending on the concrete service); however, the process of outsourcing and its results are rather problematic. The most critical aspects of the outsourcing process on the Slovak municipal level are the decision-making (decision in-house versus outsourcing), award process, and contract management. The chapter provides critical lessons, especially for developing countries and countries of post-transitional character with a lack of accountability and lack of experience with outsourcing on the municipal level.