Recent evidence has shown that an unhealthy diet is associated with a higher risk of tumor recurrence, metastasis, and death among patients with colorectal cancer (CRC). The aims of this study were to assess nutritional adequacy and diet quality in a group of CRC patients postsurgery and to identify possible associations between dietary and nutritional aspects and environmental factors and weight status. This was an observational study conducted on a random sample of 74 patients, aged 50-69 years. Dietary intake was evaluated utilizing a validated frequency questionnaire, and diet quality was evaluated utilizing the Healthy Eating Index for Spanish Diet and the MedDietScore. Data regarding socioeconomic, demographic, lifestyles, dietary supplements use, and body mass index were collected. Subjects followed a diet characterized by a low carbohydrate intake (94% of the cases), excessive protein (48%), high fat intake (67%), and some micronutrient deficiencies. The inadequacy of some nutrients was associated with male gender, overweight/obesity, smoking, and low educational level; and low adherence to the MedDiet was identified in those with a low educational level (adjusted odds ratio = 4.16, P < 0.05). Therefore, such patients should be an important target group when applying educational programs and giving individualized nutritional advice to improve their quality of life.