Coronary heart disease (CHD) represents a major global health burden. However, despite the well-known influence that dietary habits exert over the progression of this disease, there are no well-established and scientifically sound dietary approaches to prevent the onset of clinical outcomes in secondary prevention. The objective of the CORonary Diet Intervention with Olive oil and cardiovascular PREVention study (CORDIOPREV study, clinical trials number NCT00924937) is to compare the ability of a Mediterranean diet rich in virgin olive oil versus a low-fat diet to influence the composite incidence of cardiovascular events after 7 years in subjects with documented CHD at baseline. For this purpose, we enrolled 1,002 coronary patients from Spain. Baseline assessment (2009–2012) included detailed interviews and measurements to assess dietary, social, and biological variables. Results of baseline characteristics: The CORDIOPREV study in Spain describes a population with a high body mass index (37.2% overweight and 56.3% obesity) and with a median of low-density lipoprotein cholesterol of 88.5 mg/dL (70.6% of the patients having <100 mg/dL and 20.3% patients <70 mg/dL). A total of 9.6% of the participants were active smokers, and 64.4% were former smokers. Metabolic syndrome was present in 58% of this population. To sum up, we describe here the rationale, methods, and baseline characteristics of the CORDIOPREV study, which will test for the first time the efficacy of a Mediterranean diet rich in extra virgin olive oil as compared with a low-fat diet on the incidence of CHD recurrence in a long-term follow-up study.