Purpose. To use the meta-analytic approach to examine the effects of diet (D), aerobic exercise (E), or both (DE) on non-high-density lipoprotein cholesterol (non-HDL-C) in adults. Methods. Randomized controlled trials in adults ≥18 years of age were included. A mixed-effect model was used to combine effect size (ES) results within each subgroup and to compare subgroups (Qb). Heterogeneity was examined using the Q and I2 statistics, and 95 confidence intervals (CI) were also calculated. Statistical significance was set at P≤0.05, while a trend for statistical significance was set between P>0.05, and ≤0.10. Results. A statistically significant exercise minus control group decrease in non-HDL-C was found for DE (7 ESs, 389 participants, x=-11.1 mg/dL, 95 CI=-21.7 to -0.6, P=0.04, Q=2.4, P=0.88, I2=0), a trend for the D group (7 ESs, 402 participants, x=-8.5 mg/dL, 95 CI=-18.6 to 1.6, P=0.10, Q=0.76, P=0.99, I2=0), and no change for the E group (7 ESs, 387 participants, x=3.0 mg/dL, 95 CI=-7.1 to 13.1, P=0.56, Q=0.78, P=0.99, I2=0). Overall, no statistically significant between-group differences were found (Qb=4.1, P=0.12). Conclusions. Diet combined with aerobic exercise may reduce non-HDL-C among adults in some settings. © 2012 George A. Kelley and Kristi S. Kelley.