Richmond, California
July 24, 2002

Sangamo BioSciences, Inc. (Nasdaq: SGMO) today reported financial results for the second quarter ended June 30, 2002. The consolidated net loss, which includes non-cash and restructuring charges, was $3.6 million, or $0.15 per share. In the comparable quarter of 2001, Sangamo reported a net loss
of $2.4 million, or $0.11 per share. Non-cash charges were $268,000 in the second quarter of 2002 as compared to non-cash charges of $699,000 in the second quarter of 2001. These expenses were related to stock-based compensation expense and patent amortization charges. Excluding the non-cash and restructuring charges, the core operating loss was $3.4 million, or $0.14 per share, in the second quarter of 2002, as compared to a core operating loss of $1.7 million, or $0.08 per share, in the same period last year.

Revenues for the second quarter of 2002 were $366,000 as compared to second quarter 2001 revenues of $1.3 million. The principal components of second quarter 2002 revenues were Universal GeneTools(TM) revenues and revenues from Sangamo's partnerships in the areas of human therapeutics and plant agriculture.

Excluding the non-cash and restructuring charges, total second quarter 2002 expenses were $4.1 million as compared to $3.9 million in the prior year period. Research and development expenses were $3.0 million for the three months ended June 30, 2002 and $3.0 million for the three months ended June 30, 2001. General and administrative expenses were $1.1 million for the second quarter of 2002 as compared to $854,000 for the same period last year.

Net interest income for the second quarter of 2002 was $346,000 as compared to $841,000 in the comparable period last year. At June 30, 2002, the company had cash, cash equivalents, and investments of $55 million. Total shares outstanding at June 30, 2002 were 24,560,620.

Second-Quarter 2002 Highlights

Highlights of the second quarter included:

• Sangamo scientists and their academic collaborators made a total of six presentations in addition to chairing two scientific sessions at the 5th Annual Meeting of the American Society of Gene Therapy in Boston in June.
• At this meeting, Dr. Frank Giordano, MD of Yale University School of Medicine presented preclinical studies of Sangamo's lead zinc finger DNA binding protein transcription factor (ZFP TF) therapeutic. The data showed that new vasculature generated in a mouse ear model using
  Sangamo's ZFP TF designed to upregulate the endogenous VEGF gene, and consequently all of its protein isoforms, was healthier and less leaky than that generated by treatment with a cDNA encoding a single VEGF isoform. This represents a critical advantage for a therapeutic
  designed to stimulate new blood vessel formation in diseased or damaged heart or skeletal muscle. The work was carried out in collaboration with Sangamo scientists and was sponsored by Edwards Lifesciences Corporation. Sangamo and Edwards Lifesciences are collaborating to
  develop novel treatments for ischemic cardiovascular disease and peripheral vascular diseases.
• Dr. Andreas Reik of Sangamo also showed data from a collaboration between Sangamo and Onyx Pharmaceuticals. The partnership combines Onyx's therapeutic anti-cancer adenovirus with Sangamo's gene activation technology. Data presented showed ZFP TF upregulation of the endogenous granulocyte macrophage colony stimulating factor (GM- CSF) gene in a wide variety of tumor cell lines and in the presence of replicating adenovirus. It is anticipated that this therapeutic strategy will lead to the stimulation of an active immune response against a patient's tumor specific antigens and potentiate an anti-tumor antibody response to metastatic cancer.
• Also at this meeting, Sangamo scientist Dr. Carolyn Dent presented the first data demonstrating the inducible regulation of an endogenous gene using a ZFP TF whose activity was controlled by a small molecule regulatory switch. Activation of the ZFP TF and the subsequent regulation of its endogenous target gene was shown to be dependent on the concentration of a small molecule in a variety of cell types. The capability to regulate expression is important in a gene therapy application as it allows control of the duration of the therapeutic
  effect and provides greater control over dosing levels.
• Sangamo and Renessen LLC, a joint venture between Cargill and Monsanto Company, signed an agreement to extend their collaboration. The companies are applying Sangamo's proprietary gene regulation technology to enhance the value of certain crops for the animal feed and processing industries.

Six-Month Results

For the six-month period ended June 30, 2002 net loss was $8.1 million, or $0.33 per share compared to $4.5 million, or $0.20 per share, in the comparable period in 2001. Included in the six-month net loss were non-cash charges totaling $1.4 million in 2002 and $1.5 million in 2001, and restructuring expenses of $190,000 in 2002. Excluding these charges, the core operating loss was $6.5 million, or $0.27 per share, in 2002, and $3.0 million, or $0.13 per share, in the comparable period in 2001. Revenues for the first six months of 2002 were $867,000 as compared to $2.0 million in the same period of 2001. Excluding non-cash and restructuring charges, total expenses for the six months ended June 30, 2002 and 2001 were $8.2 million and $6.8 million respectively.

Sangamo BioSciences, Inc., of Richmond, CA, is focused on the research and development of novel transcription factors for the regulation of gene expression. The company's most advanced therapeutic development program involves the use of transcription factors for the treatment of cardiovascular disease. Other therapeutics development programs are focused on cancer and infectious diseases. Sangamo's proprietary technology enables the engineering of transcription factors known as zinc finger
DNA-binding proteins, or ZFPs. By engineering ZFPs so that they can recognize a specific gene, Sangamo has created ZFP transcription factors (ZFP TFs) that can control gene expression and, consequently, cell function. The company is developing ZFP TFs as a fundamentally enabling technology for commercial applications in human therapeutics, pharmaceutical discovery, clinical diagnostics, agriculture and industrial biotechnology. Over twenty leading pharmaceutical and biotechnology companies have utilized ZFP TFs.