Inflammation and coagulation pathways are implicated in circulatory disease, but their interaction has not been completely deciphered yet. In this study, we investigated the association of coagulation and inflammation indices (activated clotting time [ACT], C-reactive protein, neutrophils) in hospitalized patients. Blood samples were drawn from consecutive patients at admission and at 48 hours for the assessment of the aforementioned parameters (n = 63). Healthy controls matched for sex and age were also examined (n = 39). Activated clotting time positively correlated with CRP on admission ( r = 0.354, P = .005), while the correlation was more robust on the second day ( r = 0.775, P < .001). Activated clotting time was significantly more prolonged in patients with abnormal CRP or abnormal absolute neutrophil count compared to patients with normal inflammatory markers ( U = 55.0, P < .001 and U = 310.5, P = .035, respectively). At 48 hours, a positive relationship was observed between ACT and relative percentage of neutrophils ( r = 0.358, P = .004). These findings suggest a link between ACT and inflammation indices for the first time in humans. Further research is needed to determine whether these interrelations can be used to improve patient management.