Cow preferences for one of two compartments with different floors were tested in a barn with two symmetrical, connected compartments, each intended for 16 cows. Compartments were identical except for the floor. One floor was grooved longitudinally to the feeding barrier and the other was slotted perpendicular to that barrier. Sixteen pregnant, lactating Holstein-Friesian cows were used. After 14 d of habituation, cow behavior was videotaped for 10 full 24-h d, spread over 22 d. Their daily time budget spent on different activities performed in both compartments was analyzed, as was their relocation and use of the concentrate dispenser in each compartment. On average, cows spent 120 min longer per day in the slotted floor compartment than in the grooved floor compartment, and performed all activities in the daily time budget significantly longer in this compartment. However, testing the preference of individuals revealed that, although five cows significantly preferred the slotted floor compartment, two cows significantly preferred the other compartment, and nine cows had no preference. On the slotted floor, cows ate longer at the feeding barrier and more often drank front-on to the water trough; on the grooved floor they more often drank standing parallel to the water trough. Thus, they seemed to prefer to stand parallel to the slots. Relocation of cows, indicated by index of movement, was not significantly different between the floors. Relocation seemed to be stimulated more by the presence of concentrate dispensers in both compartments than by floor profile. Although one floor type was not clearly preferred over the other, the findings and methods of this study have implications for design and implementation of future preference tests for testing husbandry systems and their components.