This report examines actual fluid flow data for gas/oil pipelines and compares the data to two-phase flow modeling methods. Field data from eight operating pipelines was compared. Measured pressure drop and measured overall holdup for the eight gas/oil and gas/condensate pipelines examined were compared against calculated values. The gas/condensate pipelines, Marlin, Viking, Prigg-St. Fergus, Seagull, were primarily in the slug regime in the uphill direction and in the stratified regime downhill.