The LIX Legislature (59th session) of the Congress of Mexico met from September 2003 to August 2006. All members of the lower house (Chamber of Deputies) were elected in the elections of July 2003 while members of the upper house (Senate) were elected in the elections of July 2000.
|- ! style="background-color:#E9E9E9;text-align:left;vertical-align:top;" colspan=2|Parties ! style="background-color:#E9E9E9;text-align:right;" |Votes ! style="background-color:#E9E9E9;text-align:right;" |% ! style="background-color:#E9E9E9;text-align:right;" |FPP Seats ! style="background-color:#E9E9E9;text-align:right;" |PR Seats ! style="background-color:#E9E9E9;text-align:right;" |Total |- | style="text-align:left;vertical-align:top;" rowspan=3|PRI/PVEM | style="text-align:left;" |Institutional Revolutionary Party (Partido Revolucionario Institucional) | style="vertical-align:top;" | | style="vertical-align:top;" |30.6 | style="vertical-align:top;" |161 | style="vertical-align:top;" |63 | style="vertical-align:top;" |224 |- | style="text-align:left;" |Ecologist Green Party of Mexico (Partido Verde Ecologista de México) | style="vertical-align:top;" | | style="vertical-align:top;" |4.0 | style="vertical-align:top;" |3 | style="vertical-align:top;" |14 | style="vertical-align:top;" |17 |- | style="text-align:left;" |PRI-PVEM lists | style="vertical-align:top;" | | style="vertical-align:top;" |13.4 | style="vertical-align:top;" | | style="vertical-align:top;" | | style="vertical-align:top;" | |- | style="text-align:left;vertical-align:top;" colspan=2|National Action Party (Partido Acción Nacional) | style="vertical-align:top;" | | style="vertical-align:top;" |23.1 | style="vertical-align:top;" |80 | style="vertical-align:top;" |69 | style="vertical-align:top;" |149 |- | style="text-align:left;vertical-align:top;" colspan=2|Party of the Democratic Revolution (Partido de la Revolución Democrática) | style="vertical-align:top;" | | style="vertical-align:top;" |17.6 | style="vertical-align:top;" |56 | style="vertical-align:top;" |41 | style="vertical-align:top;" |97 |- | style="text-align:left;vertical-align:top;" colspan=2|Labour Party (Partido del Trabajo) | style="vertical-align:top;" | | style="vertical-align:top;" |2.4 | style="vertical-align:top;" |0 | style="vertical-align:top;" |6 | style="vertical-align:top;" |6 |- | style="text-align:left;vertical-align:top;" colspan=2|Convergence for Democracy (Convergencia por la Democracia) | style="vertical-align:top;" | | style="vertical-align:top;" |2.3 | style="vertical-align:top;" |0 | style="vertical-align:top;" |5 | style="vertical-align:top;" |5 |- | style="text-align:left;vertical-align:top;" colspan=2|Independents | | style="vertical-align:top;" | | style="vertical-align:top;" |0 | style="vertical-align:top;" |2 | style="vertical-align:top;" |2 |- |style="text-align:left;background-color:#E9E9E9" colspan=2|Total |width="75" style="text-align:right;background-color:#E9E9E9"| |width="30" style="text-align:right;background-color:#E9E9E9"| |width="30" style="text-align:right;background-color:#E9E9E9"|300 |width="30" style="text-align:right;background-color:#E9E9E9"|200 |width="30" style="text-align:right;background-color:#E9E9E9"|500 |- | style="text-align:left;" colspan=6 |Source: IFE/PREP and Grupa Reforma