The inspection requirements of the hundreds of thousands of miles of pipeline worldwide necessitates the use of high inspection velocities. Unfortunately, high inspection velocities can compromise the ability to detect and characterize defects [1,2]. These velocity effects need to be quantified in order to have a complete understanding of MFL inspection capabilities. This paper presents an explanation and a summary of these effects based on two and three dimensional finite element analysis and experimental results. Selected finite element and experimental results are also shown. The specific problem addressed is large diameter (>12 inches), ferromagnetic steel pipe material and inspection velocities up to 10 miles per hour. The defects are volumetric metal loss generally caused by corrosion.