Few Croatian clubs carry their story as visibly in their name as the football side of Varaždin. It was founded on 3 June 1931 as NK Slavija and kept that name until 1941. In 1958 it became NK Varteks, a blend of "Varaždin" and "textile", after its main sponsor, the local clothing factory. The factory's tailors gave the club its nickname Krojači (The Tailors), and for more than fifty years, until 2010, the town's industry and its football shared one identity. Throughout the Yugoslav era the club played in the lower divisions.
The real rise came with Croatian independence. From 1992 Varteks spent about two decades in the top flight, finishing third three times and reaching the national cup final six times. The best-known of those finals came in 1998, when the side coached by Dražen Besek beat Hajduk Split in the semi-final, 2–1 at home and 1–0 away. In the final they lost to Croatia Zagreb 3–1 on aggregate (0–1 in Varaždin, 1–2 in Zagreb). The cup run showed that a provincial club could compete with the biggest names in the country, even though the club never established itself as a regular challenger for the title.
The finest European chapter was written in the 1998–99 Cup Winners' Cup. The debut in this competition had come two years earlier, in 1996–97, with a 5–1 aggregate victory over Union Luxembourg in qualifying. In 1998–99 the team beat SC Heerenveen 5–4 on aggregate, with the decisive goals coming in extra time of the second leg in Varaždin. Miljenko Mumlek scored three times in the two matches. In the quarter-final they met RCD Mallorca, drawing 0–0 at home before losing 1–3 away. No other Croatian club of the period had gone so far in that competition, and the run remains the high point of the club's European history.
The key figure of that era was Mumlek, a Varaždin native and the very embodiment of the club. He played for Varteks in several spells and made more than 340 appearances, scoring around 90 goals. Another name closely tied to the club is Anđelko Herjavec, general manager of the clothing factory and president of the club, who died in a traffic accident in 2001. The home ground, Stadion Varteks, was built in 1931 next to the factory. Supporters unofficially named it after Herjavec, and the name still appears in the media today.
The story changed course in June 2010, when the factory did not renew its sponsorship and the club dropped the Varteks name to become NK Varaždin. Many supporters took this as a break with tradition, and in 2011 they founded a new club, NK Varteks, which began in the county leagues. Meanwhile, financial problems led to relegation from the top flight in 2012 and a suspension by the football federation in 2013. The historic club then restarted in the third tier before ceasing to exist in 2015. In 2012 a new club under the name NK Varaždin had appeared, which has since returned to the top flight and plays at the same stadium. The town therefore has two clubs, each laying claim to a share of the same tradition, and the history of the "Tailors" is today a story about who can rightfully inherit it.