The experiment was conducted on chia and quinoa plants at Fayoum governorate during 2019/2020 season, to study the effect of conventional and organic cultivation on diversity and abundance of spiders and other arthropods. Pitfall traps were used to collect spiders and other arthropods in the soil, while the direct counting method was used to collect arthropods on plant leaves. Higher number of spiders collected from organic cultivation (486& 251 indv.) than collected from conventional cultivation (423 &213 indv.) for chia and quinoa respectively. The most abundant family was Lycosidae in chia and quinoa. Family Lycosidae was considered "constant" and pardosa sp. was the most abundant species in two cultivations. The results revealed that chia cultivation included the highest number of dominant species in both cultivations. Total number of arthropods collected by pitfall traps recorded (5985 & 2812 indv.) in conventional cultivation and (6703 & 2951indv.) in organic cultivation chia and quinoa respectively. Arthropods on leaves recorded (643 &488indiv. in chia) and (256& 238indv. in quinoa) for conventional and organic cultivation respectively. Tetranychus urticae and Phytoseiulus persimilis were recorded on chia plants only, while Liriomyza sp. and Tuta absoluta were recorded on quinoa plants only. T. urtica and Bemisia tabaci recorded the highest dominant and abundant in chia, however Aphis spp. and Thrips tabaci in quinoa in both cultivations.