Paris Saint Germain winger Angel Di Maria was also included but there was no place for striker Gonzalo Higuain, who is on loan at Chelsea from Juventus.
"These are the ones we consider to be the best," said Scaloni, who will have to reduce his list to 23 players next week ahead of the tournament hosted by Brazil, which begins on June 14.
Argentina will play in Group B alongside Colombia, Paraguay and guests Qatar, the 2022 World Cup hosts and current Asian champions.
Messi, who only returned to the Argentina squad in March after an eight-month absence following the World Cup in Russia, will turn 32 during the competition.
Di Maria, like Messi, made his post-World Cup return in March ahead of friendlies against Venezuela and Morocco, but Aguero had not been called up since Argentina's 4-3 last 16 defeat to eventual champions France in Russia.
Argentina have not won the Copa America, or any major international tournament, since 1993, losing in the final in four of the last five editions of the continental showpiece.
Goalkeepers: Agustin Marchesin (America Mexico/MEX), Juan Musso (Udinese/ITA), Franco Armani (River Plate), Esteban Andrada (Boca Juniors), Geronimo Rulli (Real Sociedad/ESP)
Defenders: German Pezzela (Fiorentina/ITA), Gabriel Mercado (Sevilla/ESP), Juan Foyth (Tottenham Hotspur/ENG), Nicolas Otamendi (Manchester City/ENG), Walter Kannemann (Gremio Porto Alegre/BRA), Nicolas Tagliafico (Ajax/NED), Marcos Acuna (Sporting Lisbon/POR), Gonzalo Montiel (River Plate), Renzo Saravia (Racing Club), Lisandro Martinez (Defensa y Justicia), Ramiro Funes Mori (Villarreal/ESP)
Midfielders: Leandro Paredes, Angel Di Maria (both Paris Saint-Germain/FRA), Guido Rodriguez (America Mexico/MEX), Giovani Lo Celso (Real Betis/ESP), Manuel Lanzini (West Ham/ENG), Roberto Pereyra (Watford/ENG), Matias Zaracho (Racing Club), Ivan Marcone (Boca Juniors), Domingo Blanco (Defensa y Justicia), Rodrigo De Paul (Udinese/ITA), Exequiel Palacios (River Plate), Maximiliano Meza (Rayados/MEX)
Forwards: Lionel Messi (Barcelona/ESP), Sergio Aguero (Manchester City/ENG), Gonzalo Martinez (Atlanta United/USA), Paulo Dybala (Juventus/ITA), Angel Correa (Atletico Madrid/ESP), Lautaro Martinez (Inter Milan/ITA), Dario Benedetto (Boca Juniors), Matias Suarez (River Plate), Mauro Icardi (Inter Milan/ITA)