We present AGILE results on gamma-ray blazars. During the first six months of observations, AGILE detected five blazars at high significance: 3C 279, 3C 454.3, TXS 1510-089, S5 0716+71, and 3C 273. We obtained long-term coverage of 3C 454.3, for a total of about one month at energies above 100 MeV. 3C 273 was the first blazar detected both by the AGILE gamma-ray detector and by its hard X-ray monitor. S5 0716+71, an intermediate BL Lac object, exhibited a very fast gamma-ray transient during an optical high-state phase. Thanks to the rapid dissemination of our alerts, we were able to obtain multi-wavelength ToO data from other observatories such as INTEGRAL, Swift, RXTE, MAGIC, SPITZER, as well as optical coverage by means of the WEBT Consortium and REM.