This paper is devoted to the formation of a spherulitic pattern in polymers that are spatially confined. The nucleation at sample boundaries influences the spherulitic structure and accelerates the local conversion of melt into spherulites. A model of the spherulitic pattern formation in narrow strips of polymer based on the probability theory was developed to account for the effect of spherulite nucleation at sample borders. The model allows us to predict the rates of formation of the interspherulitic boundaries and also the distributions of distances from spherulite centers to the boundaries for an isothermal as well as a nonisothermal crystallization. The final length of interspherulitic lines and the final number of triple points between spherulites can also be calculated. The predictions of the model were verified by computer simulation, which reproduces spherulitic patterns observed experimentally in strips of thin films. (c) 2005 Wiley Periodicals, Inc.