This article presents a method of preparing the absorbent core for an ultrathin sanitary napkin using. super absorbent fiber (SAF) and viscose fiber blends with varying SAF percentages and mass per unit area (g/m(2)). The SAF/viscose blended carded webs were sandwiched between two layers of nonwoven fabric to integrate and encapsulate it. The prepared napkin samples showed significantly better rates of absorption for saline solution even though the glass tube wicking (gravimetric) test gave only comparable results. The saturation absorption of the core also follows a definite trend, dependent on two variables, i.e., mass per unit area (g/m(2)) of the core web and proportion of SAF in the core web. Based on the results, the absorption of the core has been optimiized and equations have been developed for prediction of the absorption of the core from mass per unit area and the proportion of SAF in the core web. (c) 2007 Wiley Periodicals, Inc.