Since 2001, Petrobras Reseach and Development Center (CENPES), is working with hybrid electric vehicles (HEV). This technology is considered quite promising, regarding emissions and fuel consumption reduction. Nowadays, its use is growing fast in USA and Japan.First studies done by CENPES Vehicle Test Laboratory with hybrid electric vehicles, pointed the need of developing battery state of charge compensation techniques, due to the fact that state of charge variation can compromise repeatability of emission and fuel consumption results. Thus, it's very important to define a methodology to test hybrid electric vehicles based on some state of charge compensation technique.Looking for appropriate compensation techniques, this paper presents a test methodology based on ISO 23274 international standard. One of the main targets was to follow some of the recommendations proposed by national standard ABNT NBR 6601 and ABNT NBR 7024 for emissions and fuel consumption measurements.To implement the proposed emission and fuel consumption test methodology, a Data Acquisition System for Hybrid Electric Vehicles was developed and acquired by CENPES Vehicle Test Laboratory. This system enables battery energy flow analysis by measuring and recording some battery parameters.To exemplify the proposed methodology, some practical results obtained up now for a TOYOTA PRIUS - year 2002 - hybrid electric vehicle are presented. The fuel used was PETROBRAS PODIUM gasoline, blended with 25% ethanol. The main objective was to implement and verify the new proposed hybrid electric vehicles emission and fuel consumption measurement methodology, qualifying Petrobras Vehicles Test Laboratory to deal with hybrid vehicle technology.