Pearlite interlamellar spacing is an important parameter controlling ductility and strain hardening of carbon steels. Fine pearlite is the appropriate initial microstructure for drawing high carbon steel with exponential strain hardening rate, leading to high final tensile strengths. The majority of optical and electron microscopy methods for measuring interlamellar spacing present difficulties when applied to fine microstructures. Atomic force microscopy (AFM) was employed to investigate pearlitic steels lead patented at 510 degrees C and then cold drawn to 86% reduction in area. Conventional specimen preparation techniques for optical metallography were appropriated to produce high resolution AFM images, on which measurements of minimum interlamellar spacing, in good agreement with spacings estimated using the Embury-Fisher model, were easily performed.