Background and aim: External humeral condyle fracture associated with a posteromedial elbow dislocation is a very rare entity, of which there are very few cases published. Our objective is to present a complex case treated in our Hospital, the diagnosis, the treatment we chose, and the follow-up at 9 weeks after the intervention. Clinical case: 5-year-old boy with a posteromedial elbow dislocation associated with an external humeral condyle fracture, which was diagnosed by CT and treated surgically using an anterior approach over the elbow, open reduction, and osteosynthesis with K-wires. Results: clinical and radiological results 9 weeks after the intervention were excellent, presenting a radiographic consolidation of the fracture and an excellent range of joint mobility. Conclusion: early diagnosis and surgical treatment through open reduction and osteosynthesis of the external condyle is the gold standard on treatment for these injuries, since a bad reduction leads to poor long-term results.