Diarrhea in Indonesia is still a disorder at high of illness and mortality rates after Upper Respiratory Tract Infection. Diarrhea was defecate more than there times a day with liquid consistency. The pupose in this study to determine the correlations between the phase of oral hygiene in infants age 6-12 months the incidence of diarrhea in Puskesmas perawatan of Simpang Empat Kecamatan Simpang Empat, Kabupaten Tanah Bumbu. This research method is analytic survey with cross sectional approach. The research data was obtained from the primary data. The population in this study are all the baby with the number of 64 respondents. The sampling technique used is total sampling.Tecnical analysis of the data using chi-square test. Data were analyzed using chi-square test with a significance of 0.05 Chi-Square test analysis results obtained there is a significant association between oral hygiene phase (P = 0.000) and the incidence of diarrhea. Conclusion The study found there is a very close Correlations between the phase of oral hygiene in infants aged 6-12 months with diarrhea occurrence in Puskesmas Perawatan of Simpang Empat, Kecamatan Simpang Empat, Kabupaten Tanah Bumbu. Hence, from the results of this research, government and comunity health centers should increasa the societys level of knowledge through counseling with a more effective method.