By plane
Either Oslo airport Gardemoen IATA: OSL or Sandefjord airport Torp IATA: TRF. They are both approximately one hour driving from Drammen. From Oslo airport Gardermoen there are several direct trains. There are 3 airport express trains per hour, these cost NOK 250,- one way and take exactly one hour. Then there's one InterCity and one regional train per hour, leaving the airport at 08 and 38 respectively, which take about 1hr 15mins and cost NOK 182,- one way.
By Rail
Most long-distance trains from Oslo travelling in the western and southern directions pass through Drammen. The following line passes Drammen: the Oslo-Skien line, the Oslo-Bergen line and the Oslo-Kongsberg-Kristiansand-Stavanger line. Drammen also has frequent local trains from Oslo.
By car
E18 from Oslo, Larvik and Kristiansand. It is a 40 min drive from Oslo, depending on the traffic. E134 connects Drammen with Kongsberg. E134 continues to Notodden and Haugesund.