Two trials were carried out on 154 Landrace x Large White piglets from birth to about 10 weeks of life to investigate the effect on growth performance of the dietary inclusion of B. coagulans CNCM I-1061 as probiotic (group P) compared to a standard diet without any additive as negative control (group C) and with antibiotic (group A: Zn-bacitracin, 80 ppm) as positive control. In the first trial on 60 piglets, daily weight gain (DWG) was significantly higher for the group P (DWG=216.7, 320.8 and 368.8 for C, A and P groups respectively). Feed conversion ratio (FCR) was better for the group A (FCR= 2.06, 1.79 and 1.85 for C, A and P groups respectively). In the second trial on 94 piglets, DWG was higher for group P in the preweaning period (4 weeks) (DWG=207.4, 196.3 and 229.6 for C, A and P groups respectively), while at the end of the trial, DWG was significantly higher for the group A (DWG=293.5, 376.1 and 317.4 for C, A and P groups respectively). No significant difference could be revealed for FCR, however the group P had the best value (FCR=1.94, 1.78 and 1.73 for C, A and P groups respectively). The rate of mortality was lower in the group P (C: 29.2%, A: 8.3%, P: 4.2%) due to reduced frequency, duration and severity of diarrhoea. Microbiological analysis was made on feed and piglet faeces. The bacterium becomes part of the enteric microflora where it is transient, and its spores prevail over those of other sporeforming bacteria. Even though there were no significant differences among the groups both the total and faecal coliforms had, in group A and P, more significant decrease than in group C. This probiotic may be considered as an alternative to antibiotics as auxinic-prophylactic for piglets provided it is administered from birth.