Introduction: Mycoplasma infection is a bacterial infection that an affect all the systems in the body , predominantly the respiratory system. It leads to an atypical infection which is also known as the walking pneumonia. However, on occasion the other systems may also be affected. Case presentation: A three-and-a-half-year-old previously well child presented with fever for 1week associated with vomiting and a cough. On admission to a base hospital the child had features suggestive of shock and required 2 fluid boluses and was managed as possible dengue shock syndrome and was transferred to the Teaching Hospital Kurunegala, PICU forfurther management. Further evaluation revealed no features suggestive of this diagnosis. However, it showed features compatible with acute liver failure grade 2 complicated with hepatic encephalopathy . During the PICU stay the child developed a bronchopneumonia, as well. He required multiple Fresh Frozen Plasma infusions and a liver failure regimen. Whileinvestigating for a possible cause the mycoplasma antibody was found to be positive. The child made a speedy recovery following the appropriate interventions. Discussion: Identification of acute liver injury is crucial as a delay in the diagnosis can lead to a detrimental outcome. One of the essentials in the management is to identify the etiology . Hence, we need to consider mycoplasma infection in any child with acute liver failure secondary to an infection so that we can start the necessary treatment early .