Besides having a valid Russian visa in your passport, at the border you are requested to fill in a Migration Card. Migration Cards might be available on board of airplane/train/bus or they can be found before the passport control at the border. If you were not provided with migration card, then ask for it before crossing passport control. Migration Card consists of 2 parts: A (Arrival) and B (Departure). You should fill both parts in block letters and hand it over to the Border Control Officer with your passport and other travel documents. Part A will be taken and part B will be stamped and then returned to you for the future registration.
Part B of migration card with the registration should be handed over to immigration officials at the border upon departure. Please note that the arrival/departure card inserted into your passport by the consulate is different from the migration card, and you have to contain both cards in your passport.
According to Russian law all types of Russian visas should be registered for the whole period of your stay within 3 days upon your arrival (excluding weekends and official Russian holidays).
If you are staying at a hotel, the hotel will register your visa for free or at a small registration fee. Please check it on reception. For the registration you should submit your passport with Russian visa and migration card.
If you are not staying at a hotel, you will have to register your visa at the Passport and Visa Department (PVO), please contact your inviting organization.
Please note if you do not register your Russian visa it may lead to serious problems: fines on departure, detention by police, prevention from boarding the plane, etc. We strongly recommend you to register your Russian visa to avoid possible inconveniences.