Вирус! (Virus! in English) - often stylized as ВИРУС! (ViRUS!) - is a Russian Euro House / Techno / Dance band.

Initially formed in December 1998 as a duo by DJ Doctor aka Юрий Ступник (Yuriy Stupnik) and Chip aka Андрей Гудас (Andrey Gudas), they soon recruited singer/songwriter Лаки (Lucky) aka Ольга Лаки (Olga Laki) aka Ольга Владимировна Козина (Olga Kozina). The group was first known as Акварель (Aquarelle) then Вот так! (Like This!) and subsequently renamed to Вирус! (Virus!) after meeting & signing with Russian producers И́горь Вита́льевич Силивёрстов (Igor Vitalievich Siliverstov) & Леонид Борисович Величковский (Leonid Borisovich Velichkovsky).

After the group gained popularity, the producers decided in January 2000 to introduce a second line-up which would tour at the same time as the real group, and would be featured in the video clips of Папа (Papa) in February 2000 and Весна (Spring) in April 2000 in order to confuse the fans. The existence of this second line-up created great tension with the original members, but it was finally revealed to the public and the producers tried to present Virus! as a six piece band. Consequently the next video clips featured both line-ups, with however dancer Vyacheslav Kazanov leaving mid-2001 and later being replaced by Vladimir Kukushkin: thus in May 2001 the video Попрошу тебя (I will ask you) only included 5 members. The conflict culminated in 2003 with the original members parting ways with former producers and, with the support of Мега Саунд (Mega Sound), suing them for the rights to the name Вирус! (Virus!) and the musical material.