Uruguay's first international rugby union match was against South American rivals Chile, in 1948. "Los Teros" were on the wrong end of a 3-21 scoreline then, but they have since become one of the highest-ranked teams on their continent, and one of the most respected teams in the second tier of test rugby.
Early versions of rugby union, brought across the Atlantic by the British, were being played in Uruguay as early as the 19th century. For many years it was a sport only played by a few teams in a few towns, but the 20th century brought more formal recognition - although it still competed with association football (soccer) for Uruguayan's attention! In 1951 the Uruguayan Rugby Union was formed.
It took until the mid-to-late 20th century for Uruguay's rugby union team to more consistently test themselves outside of South America and the Southern Hemisphere, but the increased exposure they received only served to benefit them.