We present the first installment of HI sources extracted from the Arecibo Legacy Fast ALFA (ALFALFA) extragalactic survey, initiated in 2005. Sources have been extracted from three-dimensional spectral data cubes exploiting a matched filtering technique and then examined interactively to yield global HI parameters. A total of 730 HI detections are cataloged within the solid angle 11h44<RA(J2000.0)<14h00 and +12{deg}<DE(J2000.0)<+16{deg} and redshift range -1600km/s<cz<18000km/s. In comparison, the HI Parkes All-Sky Survey (HIPASS, Meyer et al. 2004, Cat. VIII/73) detected 40 HI signals in the same region. Optical counterparts are assigned via examination of digital optical imaging databases.