Purpose: To examine the association of kangaroo mother care (KMC) on energy utilization and bonding as evidenced by reduced biochemical markers of adenosine triphosphate (ATP) degradation, hypoxanthine (Hx), xanthine (Xa), and uric acid (UA), and (allantoin), a measure of oxidative stress in preterm infants 24-36 weeks gestation. A secondary objective was to compare specific physiological parameters using bedside monitoring and perfusion and oxygenation of the gut using near-infrared spectroscopy (NIRS) during 1 hour of KMC compared to incubator care. Study design: A randomized controlled trial (RCT) examining the effects of 1-hour of KMC or 1-hour incubator care on urinary markers from samples collected 3-6 hours before and 3-6 hours after KMC. Preterm infants (n = 51) were assigned to intervention/control groups using stratified randomization based on weight. Urine concentrations of Hx, Xa, and UA, were measured using high performance liquid chromatography (HPLC) and allantoin was quantified using gas chromatography-mass spectrometry (GC-MS) methods. Bonding was measured using the Mother-to-infant Bonding Scale, a reliable 8-item self-assessment scale linking early maternal moods to difficulties in bonding. Psychometric properties have demonstrated a two-factor model, good predictive validity, a sensitivity of 0.90 and specificity of 0.80 for a threshold score ≥ 2, and acceptable internal consistency (a = 0.71). Physiologic measures were captured using bedside monitoring and abdominal NIRS to capture gut perfusion and oxygenation. Results: There was a decrease in oxidative stress (p = 0.026) in the KMC group compared to incubator group. In both groups there were trending improvements in uric acid (p = 0.025) and xanthine (p = 0.042) over time, and in abdominal temperatures (p = 0.004) and perfusion index (p = 0.031) over time. No other physiologic or urinary measures showed statistically significant changes either between the groups or over time. A mixed model analysis of variance (ANOVA) was conducted with the use of unstructured covariance matrix adjusted using the Bonferroni method to assess the changes in the outcome measures of urinary purines and physiological measures. Mother-Infant Bonding scores were calculated using relative risk. The number and percentage of subjects who changed their MIBS scores from baseline to time 3 were measured, and the comparison of these changes between the KMC on DOL 3 and DOL 4 as measured by the Mother-Infant-Bonding-Scale (MIBS) in intervention and control groups were calculated. We found that scores showed KMC mothers exhibited a higher risk of bonding problems than those in the control group. Nineteen percent more mothers in the KMC group demonstrated an increase in MIBS score or a 26% increase relative risk for an increase of score (RR=1.26; 95% CI 0.97,1.63). However, the results were not statistically significant as the null value was included in the 95% confidence interval. Significance was set at an alpha of 0.05. Conclusions: This is the first study to evaluate th...