Dr. Max Delbruck, 74, a Nobel Prize-winning biologist whose work on the life processes of tiny viruses helped lay the foundation for modern molecular biology and research into diseases believed to be caused by viruses, died of cancer Monday at Huntington Memorial Hospital in Pasadena, Calif.

Dr. Delbruck was the Board of Trustees Professor of Biology, Emeritus, at the California Institute of Technology in Pasadena.

In 1969, Dr. Delbruck, and Salvador E. Luria, an Italian-born biologist who teaches at the Massachusetts Institute of Technology, shared the Nobel Prize in physiology and medicine for providing deeper insight into the nature of viruses and viral diseases, ranging from cancer to the common cold. There work established the exacting mathematical models of the replication of phages that revolutionized biology in the 1940s. Phages are another name for bacteriophages, rapidly multiplying viruses that infect bacteria rather than ordinary cells and which serve as a model for more complicated organisms.

The two scientists met in the 1940s, while both were teaching at Indiana University. One of their pupils there was James D. Watson, who won a Nobel Prize for medicine for his work in deciphering the genetic code.

Dr. Delbruck's study of the relationship between the virus and its host bacteria helped lead to the discovery that both viruses and bacterial cells can mutate, changing their infectious charactertistics and resistance to infection.

His recent research was involved in clarifying the mechanism of one of the world's simplest "eyes," a single light-sensitive cell in the mold Phycomyces.

Born September 4, 1906, in Berlin, Dr. Delbruck was trained as a theoretical physicist, earning his doctorate at the University of Gottingen, Germany in 1930. He first came to Caltech in 1937 as a Rockefeller Foundation Fellow. He served on the faculty of Vanderbilt University in Tennessee for several years before returned to Cal-tech in 1947 as a professor of biology.

His numerous honors and awards include the Kimber Genetics Medal, the Gregor Mendel Medal, the Louisa Gross Horwitz Prize and several honorary degrees. He was a member of many scientific associations.

Survivors include his wife, Mary Adaline, of Pasadena; four children, Jonathan, of Anchorage, Alaska, Nicola and Tobias, both of San Diego, Calif., and Ludina, of Pomona, Calif., and a grandchild.