To study the effect of an educational intervention programme concerning knowledge and postural habits for back health on a group of 10 to 11-year-old students. Two groups of 5 th grade primary school students were selected. A control group (CG) (n=16), and an experimental group (EG) (n=16) who developed a back-health educational programme. A follow-up was carried out one month after the end of the intervention. The proposed educational intervention improved the results of both the knowledge and postural habits of the participants. The increase in the level of knowledge concerning health and back care in the daily lives of the EG (x̅ =6.32) was significantly greater than that observed in the CG (x̅ =3.86), with a high effect size (U = 29.500; Z = -3.717; p <0.001, r = 0.66). In daily postural habits, the EG (x̅ = 88.38) also increased their score significantly (U= 7.50; Z = -4.55; p <0.001, r = 0.80) compared to the CG (x̅ = 74.88). In both knowledge and postural habits, the scores increased in the intervention. The educational intervention programme studied improves both knowledge and postural habits for back health of the 5th grade students participating in the study. The Physical Education class seems to be an ideal environment to develop back health educational programmes.