We present the first results of a targeted survey carried out with the 305 m Arecibo telescope to detect H i -line emission from galaxies at redshift z > 0.16 . The targets , selected from the Sloan Digital Sky Survey database , are non-interacting disk galaxies in relatively isolated fields . We present here the H i spectra and derived H i parameters for ten objects detected in this pilot program . All are massive disk galaxies in the redshift interval 0.17 - 0.25 ( i.e . 2 - 3 Gyr look-back time ) , with H i masses M _ { HI } = 3 - 8 \times 10 ^ { 10 } M _ { \odot } and high gas mass fractions ( H i - to - stellar mass ratios \sim 10 - 30 % ) . Our results demonstrate the efficacy of exploiting Arecibo ’ s large collecting area to measure the H i mass and rotational velocity of galaxies above redshift z = 0.2 . In particular , this sample includes the highest redshift detections of H i emission from individual galaxies made to date . Extension of this pilot program will allow us to study the H i properties of field galaxies at cosmological distances , thus complementing ongoing radio synthesis observations of cluster samples at z \sim 0.2 .