In many countries, the morbidity and mortality rates caused by Haemophilus influenzae type b (Hib) have decreased by more than 95% since the World Health Organization (WHO) approved the introduction of conjugated vaccines against this pathogen. However, in developing countries like Colombia, which has extensive vaccination coverage, there are still manifestations of potentially fatal invasive infections due to the non-identification of this germ. We present a case of subdural effusion in an infant secondary to Hib meningitis, which was identified by real-time PCR (RT-PCR). The importance of this test is that it has a higher sensitivity (95%) versus cultures of cerebrospinal fluid (CSF) and blood that have proven not to be effective enough to establish an etiological diagnosis in bacterial meningitis. It also allows the evaluation of the impact of vaccination, especially because there are reports of the re-emergence of Hib meningitis in different parts of the world.