Metabolic and bariatric surgery (MBS) is an effective treatment option for people with severe and complex obesity. As all MBS procedures affect nutritional intake and have the most impact on micronutrient absorption, the risk of micronutrient deficiencies is increased. Appropriate management from a specialist dietitian, which includes recommendations regarding vitamin and mineral supplementation and regular biochemical monitoring of micronutrients, is vital. In this chapter, we discuss post-operative micronutrient supplementation, biochemical monitoring, identification and treatment of nutritional deficiencies, and follow-up protocols. Whilst post-operative follow-up may differ between countries and regions, it is important that patients receive support and advice from specialist dietitians and access to appropriate supplements, nutritional monitoring, and long-term follow-up.