Sediments of San Francisco Bay, California, have been analyzed for the presence of normal paraffin hydrocarbons. Normal paraffins containing 8 through 13 C atoms were not detected; those having 14 through 17 C atoms were not investigated because of the lack of an adequate technique; and those having 18 to about 40 C atoms were found in concentrations from 3 to 6 parts per million dried sediment. Among the normal paraffins containing 23 through 35 C atoms the relative abundance of molecules having an odd number of C atoms is 2 times to 5 times greater than the relative abundance of molecules having an even number of C atoms. Most crude oils contain normal paraffins having at least 8 through more than 40 C atoms. These paraffins do not show a predominance of odd-C-number molecules but are distributed so that odd- and even-C-number molecules are present in about equal amounts. If the sediments of San Francisco Bay are to yield crude oil, changes probably should take place in the molecular distribution of the normal paraffins already present. The ratio of odd- and even-C-number normal paraffins should be reduced so that odd- and even-C-number molecules are about equally abundant. Also, normal paraffins of intermediate molecular weights should be added to these sediments Additional normal paraffins may be derived from other organic materials dispersed in the sediments.