Organizacion Musical Sudamericana (OMSA) SRL is a publisher that was established in Buenos Aires in 1992 by Roberto Barry and John Nathan.

Roberto Barry was a well-known music executive and the local representative for BMI and PRS, as well as the sub-publisher for Boosey & Hawkes.

John Nathan at the time was New York based where he ran Overseas Music Services, Inc., acting as the U.S. representative for important foreign record companies and music publishers.

A study of the Argentine music publishing business showed that many foreign publishers were either not represented, or represented so poorly that they rarely if ever received royalty statements, much less monies.

It was decided to set up OMSA and to offer royalty collection services in Argentina, Chile and Uruguay, and to register with the local author societies the copyrights owned by whatever foreign publishers were represented.

It quickly became obvious that the OMSA idea was a good one and before long the company was representing many varied and important publishers, among them Wise Music, Wixen Music, Ultra, Downtown, Budde, Jobim Music, Fermata do Brasil and many others. Word of mouth indicating that OMSA accounted regularly, continued to bring publishers into the fold.

Besides that, since 2018 OMSA started to build its own local catalog working with many argentinian composers.

OMSA continues to provide top level sub-publisher services and remains the #1 independent publisher in the region. Territories covered include Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Paraguay, Peru y Uruguay.