Twenty-four crossbred pigs (Duroc x Yorkshire), 28 days old and of 6.9 kg average liveweight, were used to evaluate effects of dietary addition of 0 (control), 5, and 7.5% of wastewater from a caramel production plant (WWCP) on performance from weaning to finishing at 82 kg average liveweight and on carcass characteristics. A completely randomized block design was used (n = 4). Pigs were fed at the rate of 8% of body weight daily during the postweaning phase (21 days) and 6% for the rest of the experiment. During the post-weaning phase dry matter intake, liveweight gain and feed efficiency were improved with 7.5% but not with 5% addition of WWCP (P ≤ 0.08). During the fattening phase (until 74 kg average liveweight), daily dry matter intake and daily weight gain were greater in the control group, whereas during the finishing phase (14 days), feed efficiency improved with the addition of either level of WWCP (P ≤ 0.08). Longissimus dorsi area and ham weight were greater in females than in barrows (P ≤ 0.05), but no other differences due to the dietary addition of WWCP were detected. These results suggest that swine growth during the first three weeks post-weaning may be improved by the addition of WWCP to the diet at levels of up to 7.5%. However, before further recommendation can be given, additional research is needed on the effectiveness of the use of this wastewater during the fattening-finishing phase. Freshness of this byproduct seemed to have an important effect.