Some drove their pink-and-white cabs in ranks, snarling traffic along the city's main boulevard.
The drivers say that Uber and other ride-sharing services evade the tax, registration and safety laws that regular cabs are subject to.
Taxi drivers' leader Eleazar Romero told the rally that "we are not against technology. We just want a level playing field, we want everyone to follow the same tax rules we do." Uber responded on its blog by offering Mexico City commuters free rides today, with hashtag that roughly translates as "If Mexico won't stop, Uber won't stop."