Correct nutrition during pregnancy is key to guaranteeing success at this stage of a woman's life, and nutritional education is the fundamental tool for achieving this. Studies carried out in different countries indicate that pregnant women do not comply with dietary and nutritional recommendations. Given the lack of evidence available in Spain and the importance of this knowledge to be able to assess the need for nutritional intervention in this group, the aim of this study focused on the current status of the issue in Spain: the quality of the diet of Spanish pregnant women and its conditioning factors. Two representative regions of the country were selected, one located in the north of Spain (Burgos) and the other in the south (Granada), and a descriptive, cross-sectional observational study (sample size: 771) was carried out using a questionnaire administered at the University Hospital of Burgos and the Hospital Clínico San Cecilio in Granada, which had previously been subjected to a process of evaluation by expert judgement. Pregnant women presented an adequate diet quality (8.0 ± 2.0), according to the questionnaire used, despite their poor knowledge of food and nutrition (4.9 ± 1.6 out of 10). However, deficiencies were detected in the consumption of very interesting food groups from a nutritional point of view, such as legumes, nuts and fish (just 29.4%, 37.6% and 24.8% of the pregnant women met the recommendations, respectively) and insufficient physical exercise. The eating habits of pregnant women depend on their age, their country of origin, their level of education, their pre-pregnancy BMI, the knowledge acquired during pregnancy and the degree to which they put into practice the advice received from their midwife. Most pregnant women do not change their habits during pregnancy, although there are positive trends in this respect. The quality of the diet of the Spanish pregnant women surveyed, and their level of physical activity, could be improved by enhancing the nutritional education they receive during this stage of life. The role of the dietician in this respect, as part of multidisciplinary teams, should be the basis for future research.