To study the contents and distribution of inorganic nutrients in the Bohai Sea of China, two cruise surveys were undertaken in August (summer) 2000 and January (winter) 2001, respectively. A total of 595 water samples were collected from 91 stations and five nutrients, i.e., nitrate, nitrite, ammonia, phosphate and silicate, were analyzed for each sample. The results show that the average concentration of dissolved inorganic nitrogen (DIN) in the Bohai Sea in winter (6.529μmol L-1) is significantly higher than that in summer (3.717μmolL-1 ). The phosphorus concentration in winter (0.660μmolL-1) is also significantly higher than that in summer (0.329μmol L-1). Mean silicate concentration in winter (7.858μmolL-1) is, however, not significantly different from that in summer (7.200 μmol L-1 ). Nutrients also vary considerably in different areas in Bohai Sea. DIN concentration in the Laizhou Bay (4.444μmolL-1 ), for example, is significantly higher than those in the Bohai Bay (2.270μmol L-1 ) and Bohai Strait (2.431μmol L-1 ), which is caused by the discharge of large amounts of nitrogen into Laizhou Bay via Yellow River. The nutrients show different vertical distribution patterns. In summer, nutrients in bottom layer are generally richer than those in surface and middle layers. In winter, however, nutrients are not significantly different in different layers. Compared with historic data, DIN contents have increased continually since the early 1980 s. Based on atomic ratios of different nutrients, nitrogen is still the limiting factor for algal growth in the Bohai Sea.