Ten Italian Friesian female calves were housed in individual stalls of two different dimensions (0.73 m x 1.21 m vs 1.00 m x 1.50 m) during the 1st month of life in order to evaluate the effect of space on the welfare of dairy calves. Behavioural observations were made on d 2 to 3 (period 1) and on d 28 to 29 (period 2) during daylight using a time-lapse video recording system. At 10, 20, and 30 d, blood samples were taken and analysed with phytohemagglutinin stimulation to determine lymphocyte proliferation. During the second period, the calves in large stall spent more time lying (P<0.05) and grooming (P<0.001), and the calves in small stalls exhibited more time searching for feed (P<0.001). Lymphocyte proliferation was statistically lower in calves housed in smaller stalls (P<0.01). Moreover, lymphocyte proliferation was negatively correlated with time spent searching for feed (P<0.01).