Swimming at the 2018 Summer Youth Olympics – Boys' 4 × 100 metre medley relay
The boys' 4 × 100 metre medley relay event at the 2018 Summer Youth Olympics took place on 10 October at the Natatorium in Buenos Aires, Argentina. Results

Heats
The heats were started at 11:01. Final
The final was held at 19:32. References

Swimming at the 2018 Summer Youth Olympics