PURPOSE: To investigate the influence of dark chocolate (DC) supplementation on resting and steady state exercise metabolism in a group of recreationally fit/athletic females. METHODS: Using a randomized, double-blind design, 18 exercise trained female subjects were assigned to a 30-d supplementation with either 20g•d-1 of 70% DC (n = 9) or a calorically matched white chocolate (WC) (n = 9). Prior to supplementation (PRE), subjects underwent indirect calorimetry assessment for resting energy expenditure (REE) followed by an assessment of exercise energy expenditure (EEE) consisting of steady state cycling for 20 min, 10 min at 50 watts (EEE-50) and 10 min at 100 watts (EEE-100). Upon completion of the 30-d supplementation (POST), subjects repeated the assessment for REE-0, EEE-50, and EEE-100. All data are presented as mean (SE). RESULTS: Pre-supplementation REE (DC 1455 ± 49, WC 1566 ± 49 kcal•d-1, p ≥ .05), EEE-50 (DC 4.85 ± 0.15, WC 4.60 ± 0.15 kcal • min-1), and EEE-100 (DC 7.06 ± 0.16, WC 6.76 ± 0.16 kcal•min-1) were not significantly different between groups (p ≥ .05). Post supplementation REE was significantly increased by 9.5% in the DC group (Δ REE: DC 138 ± 21, WC -30 ± 21 kcal•d-1, p = .001). Neither EEE-50 (DC 4.48 ± 0.16, WC 4.47 ± 0.16 kcal•min-1) nor EEE-100 (DC 6.50 ± 0.17, WC 6.63 ± 0.17 kcal•min-1) were significantly different between groups (p ≥ .05). There was no significant difference within or between group time effects for substrate utilization at rest or during EEE-50 or EEE-100 (p ≥ .05). CONCLUSION: To our knowledge this is the first study to demonstrate that a relatively small daily dosage of DC can significantly elevate REE but does not impact steady state EEE or substrate utilization in a group of athletically fit females.