In 2005, following the seroconversion to hepatitis B in a patient who had undergone surgery, an investigation was immediately launched to identify the source of the infection. The evidence gathered during the investigation led to the conclusion that transmission likely occurred from a healthcare worker to the patient. The audit of practices revealed a number of deficiencies that may have played a role in this transmission, though it did not clarify the exact mode of transmission. This finding underscores the importance of adhering to standard precautions and guidelines for good clinical practice. (R.A.)