The Sports Club "Sęp" in Żelechów was established in 1921 at the Volunteer Fire Brigade. The founders were Antoni Gronkiewicz and Henryk Bronicki. The beginnings were modest - there was a lack of a proper pitch and equipment, and matches were played on the town's market square. Nevertheless, football was gaining increasing popularity among the residents. In the 1930s, there was a rivalry between the fire brigade team and the Jewish team, which unfortunately led to tensions and anti-Semitic incidents. In 1934, the team was reorganized and adopted the name "Sęp". In the years before World War II, the club developed dynamically, but its activities were interrupted by the war.
After the war, in 1947, the team was reactivated. The club changed its name several times, adopting names such as "Włókniarz", "Związkowiec", "Start", and "Żelechowianka". In the 1950s, the club gained prominence, and in the 1982/1983 season, "Sęp" achieved its greatest success, participating in the III league matches. Currently, the team plays in the Masovian district league.
An important aspect of the club's history was also the hockey section. Hockey in Żelechów developed mainly thanks to the passion and commitment of Miecio Krawczyk, a physical education teacher. The "Sęp" hockey team achieved successes, including defeating the START Warsaw team.
The "Sęp" club in Żelechów has a rich history and many famous players, including Janusz Białek and Marek Parzyszek. Thanks to the involvement of many people, the club has become an important element of the sports culture in the region.