The review aims to systematically assess the evidence related to human health outcomes when an organic diet is consumed in comparison to its conventional counterpart. Relevant databases were searched for articles published to January 2019. Clinical trials and observational research studies were included where they provided comparative results on direct or indirect health outcomes. Thirty-five papers met the criteria for inclusion in the review. Few clinical trials assessed direct improvements in health outcomes associated with organic food consumption; most assessed either differences in pesticide exposure or other indirect measures. Significant positive outcomes were seen in longitudinal studies where increased organic intake was associated with reduced incidence of infertility, birth defects, allergic sensitisation, otitis media, pre-eclampsia, metabolic syndrome, high BMI, and non-Hodgkin lymphoma. The current evidence base does not allow a definitive statement on the health benefits of organic dietary intake. However, a growing number of important findings are being reported from observational research linking demonstrable health benefits with organic food consumption. Future clinical research should focus on using long-term whole-diet substitution with certified organic interventions as this approach is more likely to determine whether or not true measurable health benefits exist.