In the California San Joaquin Valley (SJV), the cotton aphid (Aphis gossypii Glover) has escalated from an occasional pest to an annual, severe pest over the last 10 years. Starting in about 1994, infestations have occurred during any portion of the growing season with the infestations during the squaring/boll-filling and after boll opening periods being of the most concern. In 1995 and 1997, the cotton aphid was assessed as the most economically important arthropod pest of SJV cotton, exceeding the traditionally important pests of spider mites and lygus bugs. Although the cotton aphid is not a new insect in the SJV, the change in the bionomics of this pest dictated that updated research be conducted on the biology, damage thresholds, management, etc. of this pest. A brief review of this research will be reported herein, as well as a discussion of the status of cotton aphid in the SJV. Some directions for future research will be outlined.