Genentech's DNA In 1976, Herb Boyer and Bob Swanson sat down over a couple of beers, scratched some notes on the back of an envelope and imagined a company that would change the course of medicine. They were driven by the excitement of revolutionary science and the prospect of helping patients to do something that had never been done before — use recombinant DNA technology to produce new medical treatments. Together, our founders and the early employees created a unique culture that supported their shared passion for making a difference.

Thirty-two years later, Genentech has approximately 11,000 employees. Although the company has evolved over the last three decades, we believe there is a "DNA" to our culture, an underlying code that stays fairly constant as we grow and adapt to changing circumstances. Below is how we think about these fundamental elements that have defined us from the start and upon which we continue build.

We Know Why We Come to Work Every Day (And It's Not the Free Espresso) We don't wonder about the purpose of our jobs at Genentech. Helping people with difficult-to-treat diseases provides a common mission for all of us and drives us to work hard and with a sense of urgency. We focus our drug discovery efforts on unmet medical needs — serious or life-threatening illnesses where there is a need for safer and more effective therapies — because we believe these are the areas where we can make the biggest difference. We spend every day thinking about matters of life and death, and we feel a great responsibility to do our best work. However, we counterbalance this seriousness with an environment that is casual. For instance, most days you'll find our CEO wearing jeans and sneakers as he prepares his espresso, and it's not unusual to walk into the research labs and hear AC/DC blaring while scientists conduct experiments in search of important discoveries. We refer to this combination of gravity and informality as "casual intensity," and we believe it is part of what has made us successful.

We're Science Geeks (And Proud of It) At Genentech, we focus on basic scientific research that is rooted in our ever-increasing understanding of the biological and genetic basis of disease. We believe strongly that rigorous basic research is the key to identifying breakthrough medicines for patients. Indeed, we place science at the center of our business in a way that is more typical of research universities than drug companies, and our scientists publish in prestigious peer-reviewed journals like professors do. Furthermore, a scientific sensibility permeates the company and can be felt in daily interactions and communications. This sensibility is characterized by a dedication to rigor, accuracy and data in decision-making; a pride in our work combined with a profound sense of humility in the face of all we don't know; a commitment to intelligent risk-taking; a strong belief in the necessity of collaboration for producing the best thinking and work; and an irreverence that means employees regularly ask "why?" as well as "why not?"

We Each Have Different DNA (And We Like It That Way) We place great importance on our employees, and we strive to make each individual feel valued for his/her contributions to the company's mission. From the start, we have known that we needed to recruit and retain highly talented people in order to do important new science and advance the world of medicine. We aim for every employee to feel that their unique ways of thinking are welcomed and that they can take the initiative to propose projects they believe are important to the company's success. We also encourage employees to bring their idiosyncratic and playful ways of expressing themselves and celebrating life to our demanding workplace. For this reason, you'll find employee-run clubs that run the gamut from African Americans in Biotechnology and VIDA (Latino Professionals at Genentech) to the Amateur Radio Club and the Belly Dancing Club. As a company focused on biology, we have a great appreciation for the diversity in both nature and human nature.

FORTUNE Article Read a description of our culture (PDF/146K) by FORTUNE reporter Betsy Morris from January 2006, when we were ranked #1 on the magazine's list of the "100 Best Companies to Work For."