OBJECTIVE This study assessed the proportion of children with dental fear, the proportion of children with negative behavior and the relationship of children's dental fear and children's negative behavior in private pediatric dentistry practices in western Washington state. METHODS A total of 421 children seen in 21 private pediatric dentistry practices in western Washington State participated. The average age of the children was 6.8+/-2.8 years (range=0.8-12.8 years). An average of 21 children were studied per practice (range=7-25 children). Dental fear was measured using the parents' version of the Dental Subscale of the Child Fear Survey Schedule (CFS). Behavior of the child during treatment was rated using the Frankl scale. Additional data were collected regarding the child's previous experiences and parental fear. RESULTS The children's average item score on the 15-item CFS was 2+/-0.7, corresponding to a total score of 29.6 out of 75, where 75 indicates maximum fear. The proportion of children with dental fear, defined as an average item score of > or = 2.5 (corresponding to a total score of > or = 38), was 20% (85/421, 95% CI=16.3, 24%). The proportion of children who displayed negative behavior during treatment was 21% (95% CI=17.5, 24%). A prevalence ratio of 2.4 was calculated to describe the relationship between children's behavior during treatment and children's dental fear prior to dental treatment. Multivariate logistical regression analysis showed children with dental fear, younger children, and children exposed to treatment involving local anesthesia have higher odds of displaying negative behavior. CONCLUSIONS The proportion of children with dental fear in private pediatric dentistry practices was 20%, and the proportion of children with negative behavior during treatment was 21%. Children with negative behavior had greater odds of having dental fear and children with dental fear had greater odds of having negative behavior. Screening for dental fear may allow pediatric dentists to prepare children more adequately for positive treatment experiences.