Three Characteristic Duos for Euphonium and Tuba was composed in 2020 especially for Mauro Martins and Sérgio Carolino. In the summer of that year, I asked Sérgio Carolino to record my Twenty Characteristic Etudes for Tuba on CD, in celebration of thirty years of the prize winning etudes. He was very interested in doing the project as he said he himself was introduced to these etudes many years before when he was a student. After a few discussions, he suggested adding euphoniumist Mauro Martins to the project to record some of the euphonium etudes. In addition, by writing a second line to three of original tuba etudes, I composed a set of three duets for euphonium and tuba that they could record. In selecting which etudes to make into duos, I chose #5, #6 and #17 for the set. Etude #5 has a jazz feeling since it is based on jazz harmonies and rhythms. Etude #6 is a very melodic etude, also used as the theme in the Concertino for Euphonium and Band (1996), later adapted for Concertino for Tuba and Band. For the third and last movement in the set I chose Etude #17 as it is very rhythmic and in the meter of 5/8. This set of duos is a little less than ten minutes in duration, which I thought would be a good length for a recital situation.