The objective of this study was to provide information on oral hygiene status of children while hospitalized including parental knowledge and oral health care, also to be used as a guideline to improve oral hygiene for children who are hospitalized. The study was performed in 30 patients in pediatric ward, aged 3 to 7 years. Assessment of oral hygiene status was done by measuring the plaque index before and during hospitalization, parents’ knowledge about factors affecting dental caries and behavioral changes of dental health care of children while in hospital was collected by one-on-one structured interview. Data were analyzed using descriptive statistics in percentage, mean and the different plaque index values with T-Test statistics. The study was found that oral hygiene status in hospitalized children are at a very poor level compared to before admitted with an average plaque index of 89.1 points and 69 points respectively with statistical significance (p<0.001). Level of knowledge about factors affecting dental caries of parents was at a high of 43.3 % and was at moderate of 40 %. More than 90 % of parents know that mouth cleaning, sweets or flour or sugar eating, drinking sweetened beverages or milk, and eating between meals affecting the occurrence of tooth decay. Dental health care while in hospital was found that self-brushing decreased by 80 %, brushing by parents decreased by 63.3 %, and sleeping with a bottle increased by 30 %. The results of the study concluded that oral hygiene status and oral health care behavior of children have negative change while hospitalized. There was a statistically significant increase in plaque index values and decrease in self brushing and brushing by parents. Most parents had a high and medium level of knowledge about factors that affect the occurrence of tooth decay.