Introduction: Lithium is the drug of choice for the treatment of bipolar affective disorder. Objective: To define lithium therapeutic profile and adverse reactions to its use in patients with bipolar affective disorder in Colombia. Materials and methods: We conducted an observational retrospective cohort study between January 1 and December 31, 2013, which included patients with a diagnosis of bipolar disorder treated with lithium carbonate in 25 Colombian cities; we evaluated socio-demographic variables, lithium dose, co-medication, drug interactions and adverse reactions. A multivariate analysis was done using SPSS 22.0. Results: The 331 patients had an average age of 44.5 +/- 13.9 years; 59.2% were women. The mean dose of lithium was 898 +/- 294 mg/day; 22% received doses lower than recommended, and patients had received lithium for 38.0 +/- 39.5 months (range: 12-159 months). Lithium levels in blood had been measured only in 13.5% of patients; 71.3% of them had received adjuvant therapy for bipolar disorder with other drugs, especially clozapine (16.6%) and valproic acid (16.6%). The main comorbidities were hypothyroidism (18.1%) and hypertension (12.7%); 390 potentially toxic drug interactions were found, and adverse reactions were reported in 1.2% of patients. A statistically significant association was found between a lower risk of combination therapy and receiving treatment in the cities of Bogota (OR=0.4, p=0.025), Cartagena (OR=0.3, p=0.015) and Ibague (OR=0.3, p=0.025). Conclusion: Lithium was generally used at recommended doses and intervals, but a significant percentage of patients received lower doses than those recommended, and it was not possible to compare with lithium levels in blood. Adverse reactions and blood lithium levels reporting should be improved in patients with bipolar disorder in Colombia.