Chi Chapter was first organized as Beta Chapter of Kappa Tau Fraternity. Kappa Tau was organized on the campus of Davis in 1919. With considerable interchange of students between Davis and Berkley, a second chapter was started on the Berkley campus in February of 1922. By March of that same year, a house was secured and membership had grown to forty.
Members of Kappa Tau became aware of Alpha Gamma Rho Fraternity in the process of organizing a third chapter of Kappa Tau on the campus of Oregon Agricultural College, now Oregon State University. Interest grew to the point where it was decided that both houses would petition to join Alpha Gamma Rho. These petitions were rushed to the National Convention in time for action that year. The Davis house received theirs first.
Both petitions were accepted at the Lincoln, Nebraska Convention on April 26, 1923. On the evening of May 21, 1923, thirty-six men were initiated forming Phi Chapter at Davis. On the afternoon of May 22, 1923, twenty-seven men were initiated forming Chi Chapter on the Berkley campus.
Fall 1923 brought disaster as a fire at the Chi house in Berkley destroyed the house and everything in it. Operations were moved to an apartment for the remainder of the year. Outstanding brotherhood overcame adversity and made it possible to furnish another house by the spring of 1924.
The 1930's brought problems for Chi Chapter. Changes away from an agricultural based curriculum at Berkley made it difficult to find students qualified for membership. Many other fraternities were also experiencing hard times and many folded. An all out effort was made to save the chapter. This prolonged the Chapter's life but could not save it. The National Council had authorized initiation of non-ag students in an effort to secure enough members. It maintained the Chapter for a short period but eventually produced a divided house. Chi Chapter expired in 1940, with the remaining men transferring to Davis and affiliating with Phi Chapter.
Thirty-six years later, sixty-eight Phi and Chi members from the 20's were reliving their fraternity days in a true roaring 20's fashion at a reunion on the Davis campus. Three hundred miles to the south in San Luis Obispo, twenty-one Brothers were just completing their first year as a colony. Brothers of Alpha Sigma had assisted interested students at Cal Poly in starting a colony on March 26, 1969.
Headquartered in a rented house with a capacity for twelve men, the colony began its first pledge class that same fall. The next year they became the first officially recognized fraternity on campus. Five years after its start, the colony accomplished the first step in the effort to become a chapter. The colony's petition was accepted at the 43rd National Convention in the summer of 1974. That fall, the colony waited for word on when formal initiation would take place.
As a result of favorable response from Chi Chapter members, the colony requested to re-establish Chi Chapter at Cal Poly. Early in the spring of 1975, the National Office gave its approval not only to initiation but also to the Chi name, and a date was set. On May 31, 1975, thirty-five years after the chapter at Berkley had folded, seventy-eight men were initiated by the officers of Alpha Sigma Chapter from Fresno State, reactivating Chi Chapter.