The purpose of this study was to assess the short-term effect of a physical fitness program on physical self-concept and physical fitness elements among primary school students. Spanish boys and girls (N = 75; M age = 11.1 yr., SD = 0.4) were divided into an experimental group and a control group. During physical education classes, the experimental group performed an 8-week program including two circuits of 8 exercises done for 15 to 35 sec. each with 45 to 25 sec. of rest between them. Physical self-concept (Physical Self-Description Questionnaire) and physical fitness (EUROFIT battery tests) were measured at the beginning and at the end of the physical fitness program. The results showed that the improvements in physical fitness were not accompanied by major changes in physical self-concept, even though the physical fitness program seemed to maintain the Experimental group's previous physical appearance, strength, and self-esteem perceptions, all of which statistically significantly decreased in the control group after the intervention.