Acute pancreatitis (AP) is associated with the intensive inflammatory response in white blood cells (WBC) and C-reactive protein (CRP). This paper presents the relationship between the CRP plasma concentration and the direct counts of peripheral WBC in AP during the initial five days. The study consisted of 56 patients with AP, 36 patients with mild form of AP and 20 patients with severe form of AP. ABX VegaRetic hematological analyzer was used to perform the count of blood cells, and the immunonephelometric method was performed to measure the CRP concentration levels. AP patients presented with WBC count values in the range of 3.2 − 22.4 × 103/µl and CRP concentration levels in the range 3.3 − 599.8 mg/l. The WBC count correlates with CRP levels during the entire observation period. The relationship of CRP and WBC is expressed in the following regression equation: WBC (103/µl) = 3.66 + 1.40 × logeCRP (mg/l). The highest median neutrophil count (8.15 × 103/µl) was observed on the first day. The count decreased to 5.27 × 103/µl on the fifth day. The most substantial finding in this study involved the values found for the monocytes and CRP (r= 0.53; p<0.001). Day two and day three were the highest (r=0.59, p<0.001). On day two, the regression equation for this relationship is: Monocytes (103/µl) = −0.34 + 0.21 × logeCRP(mg/l). The correlation between direct monocyte count and plasma CRP concentration in AP reflect a CRP-dependent stimulation of IL-6 release from activated blood monocytes.