The aim of this study was to assess whether in utero tobacco smoke exposure alone affects early-life lung growth and development. Pregnant BALB/c mice were exposed to cigarette smoke from six cigarettes per day, or air, from day 8 to 20 of gestation. At 2 weeks of age, pups were weighed and had their lung volumes and lung mechanics measured. Pups born from mothers exposed to cigarette smoke (CS pups; n=17) were significantly lighter (6.76 ± 0.76 versus 7.72 ± 0.68 g) and had lower lung volumes (0.123 ± 0.02 versus 0.149 ± 0.02 mL) than control pups (n=20). Respiratory mechanics were adversely impacted by cigarette smoke exposure. CS pups had higher baseline airway resistance, tissue damping and tissue elastance. These differences were largely due to lower lung volumes. Both tissue damping and elastance were increased excessively in CS pups at high transrespiratory pressures, while other parameters were not affected. There were no histological differences between groups. In utero tobacco smoke exposure significantly affects growth and development in BALB/c mice. These impacts may partially explain the susceptibility of infants born to smoking mothers to early respiratory disease and chronic respiratory disease as adults.