Background: In Egypt, cannabis is on the top list of the substances abused according to statistics of Fund for Drug Control and Treatment of Addiction. Its widespread use translates to greater access for children. Cannabis intoxication in young children can cause encephalopathy and coma. Aim: to evaluate the prevalence of acute cannabis intoxication in pre-school children (less than 6yrs) in Egypt; analysis of different factors related to the problem, clinical picture, management, assessment of severity and outcome of the problem by poison severity score (PSS). Method: prospective observational cross sectional study carried on all pre-school children (less than 6yrs) of both sex who admitted to PCC-ASUH, during the period from first of March 2019 to the end of December 2019, with history of acute cannabis intoxication and confirmed by cannabis positive screen. Results: The prevalence of acute cannabis intoxicated pre-school children (less than 6yrs) was 89.9%.The mean age was (17.38 month ±8.75). Fifty four percentages were males. As regard PSS, the majority of patients (55.1%) were of group II, while (31.4%) were of group I & (13.5%) were of group III. Regarding clinical manifestations; tachycardia observed in (5.8%), hypertension in (13.5%), tachypnea (18%), drowsiness (31.4%), muscle rigidity (21.5%), extra-pyramidal manifestations presented in (21.5%), coma grade I in (67.7%), coma grade II in (0.9%), respiratory distress in (1.8%), vomiting in (17.9%), mydriasis in (13%), miosis in (18.8%), flushed skin (12.1%) and respiratory acidosis (26.5%) of patients .ICU admission occurred in (68,7%) of patients and the majority were admitted ≥24 hours (65.9%). Conclusions: The prevalence of acute cannabis toxicity in pre-school children (less than 6yrs) has dramatically increased. Severity of acute cannabis intoxication in pre-school children(less than 6yrs) can be evaluated simply by using PSS. Recommendation: Public education is very necessary to decrease the problem. Early arterial blood gas analysis with careful neurological examination could help in identifying patients at risk.