Introduction: Low birth weight (LBW) (<2,500g) is cause of mortality and morbidity. One of its consequences is the motor impairment associated with alterations in the white matter, especially the corticospinal tract and the corpus callosum. The Kangaroo Mother Care (KMC) is an alternative to conventional care for LBW infants that consists of skin-to-skin contact, breastfeeding and early hospital discharge, and has been shown to reduce the risk of morbidity and mortality. Objective: The objective of this study was to evaluate the KMC effect on long-term motor development compared to conventional care in a cohort of 441 young adults with a history of LBW, mostly preterm, from a randomized controlled trial (RCT) carried out between 1993 and 1994, having as reference group 50 young people born at term with normal weight. Methods: Transcranial Magnetic Stimulation (TMS) was used to evaluate motor cortex development, corticospinal pathways and interhemispheric interactions through the corpus callosum and the Nine Hole Peg Test (9HPT) for the clinical evaluation of fine manual dexterity. Results: The analyzes by groups revealed a greater time in the 9HPT and less prehension force in the LBW subjects, independent of the type of intervention, with respect to the reference subjects. In contrast, no significant intergroup differences were found between the LBW subjects according to the intervention for the variables of motor interest, so they were disaggregated in the preterm and term, finding worse times in the 9HPT in the preterm subjects who received the KMC compared to those who received conventional care. No differences were found in the group analyzes in any of the neurophysiological measures of TMS between the subjects who received the KMC and conventional care, however, the multivariate logistic model showed that the KMC reduces the risk of developing by 71% (IC 95% 3-92%) alteration of transcallosal conduction time (TCT) in subjects born preterm. Conclusion: We check the heterogeneity of the subjects grouped within LBW category. Alterations in fine manual dexterity and grip strength associated with LBW persist in adulthood. The KMC seems to have a positive impact on interhemispheric communication between primary motor cortices and its effectiveness is 71% in preterm LBW subjects. TCT is a subclinical marker of neurophysiological disorders that may be associated with motor outcomes in subjects with LBW.