The resistivity data of κ-(BEDT-TTF) 2 Cu(NCS) 2 single crystals show large superconducting fluctuation effects in the presence of a magnetic field applied perpendicular to the conducting planes. These effects manifest themselves a) in a broadening of the transition into the superconducting state and b) in a melting transition of the vortex lattice into a vortex liquid. The former is investigated by employing a scaling analysis, resulting in temperature-dependent values for the upper critical field. The latter is confirmed by identifying the line of vanishing resistivity with the melting line.