BACKGROUND This study was carried out to record maximum occlusal bite force (MOBF) in pre-school children with different occlusal patterns. METHODS A randomly selected sample of 1085 kindergarten children in primary dentition stage were selected. The age of subjects ranged between 3-6 years (averaged 4.90 ± 0.86 years). The subjects were divided into 3 groups according to molar relationship; flush terminal (n=335; 165 males and 170 females), distal step (n=450; 200 males and 250 females), mesial step (n=300; 150 males and 150 females) molar relationship. Clinical examination involved the record of molar relationship, overjet, overbite and the presence of wearing facets. Occlusal bite force was measured using a hydraulic occlusal force gauge. RESULTS The means of MOBF for the different occlusal relationship were: - 193.47N (± 60.98), 179.20N (±56.80) and 245.11N (±69.45) for flush terminal, mesial and distal step molar relationships, respectively. Significant differences between studied groups were detected (P<0.01; P<0.001). MOBF were higher in subjects with distal step molar relationship, increased overjet and increased overbite. Gender differences were detected in flush terminal and distal step molar relationships. CONCLUSIONS MOBF was affected by the different occlusal relationships. Children with distal step and mesial step molar relationship had the highest and the lowest MOBF, respectively. MOBF was similar in children with/without wearing facets. Key words:Occlusal, Bite force, primary, dentition, Pre-school.