One of the more important economic activities in the Altiplano region is raising livestock, the exploitation of cattle, sheep, and llamas which are raised and adapted to the conditions surrounding this activity. Livestock production plays a fundamental role in the economy of farming families by providing them products such as meat, milk, cheese, fiber, skins, and other products that each translate into monetary revenues. The present study was carried out in the community of "Chama 6 de julio," Ingavi Province, Department of La Paz, about 83 km. (51.6 miles) outside of La Paz at an elevation of 3,792 m. (12,440 ft.) above sea level. The annual precipitation is 370 mm. (14.6 inches) and average annual temperature is 12° C (53.6° F). The set objectives of this investigative work were: To evaluate the economic behavior of the livestock production (cattle, sheep, and llamas) at the small ranchers 14 level. To quantify in monetary units the structure of costs and revenues of livestock activity. To carry out a socio-economic analysis of the activity. The statistic parameters used were: measures of means, deviations, and percentages. Techniques used for gathering information include the following: semi-structured interviews, dynamic polls, dialogues, conversations, key informants, and direct observation. In studying the costs and revenues of livestock activity the conventional model of fixed and variable costs was used. The method utilized to evaluate the activity is an adaptation of the economic evaluation expressed by the indicating gauges Cost-Benefit Relationship (RBC) and Annual Investment Profitability (RI). 42 families dedicated to agricultural and livestock activity were involved in the study. They were functionally classified according to the number of cattle that they have on their land, a classification that resulted in four groups. The first group contained families possessing from 4 to 6 cattle; the second, from 7 to 9; the third, from 10 to 12; and the fourth, the families with 13 to 15 cattle. Also, the number of samples for each class was calculated to be 5 families. As livestock activity is the most important for families in this community, these families have most of their money invested in their herds, investments ranging from 73% to 86% of all their active livestock investments. The other 14% to 27% of their investment is in the livestock infrastructure, tools, materials, and equipment. The amount of land possessed by families in this community ranges from 8 to 40 hectacres (19.8 to 98.8 acres). The meat (cattle, sheep, and llama) is the most important product for commercial purposes. Accordingly, families from class IV achieved the highest production with 812 kg. (180.7 lbs) per year, followed by classes III and II. The lowest annual amount came from families grouped into class I with only 235 kg. (518 lbs). Another product of utmost importance after meat is cheese for which the families of class IV were those that had the highest annual production with 476 units, with an average weight of 0.6 kg (1.3 lbs). They were followed by families in classes III and I. Finally, the families in class II achieved the smallest output with 337 units. 69% to 79% of the total production of meat and cheese is destined for market. The families consume only 10% to 31% of what is produced. Variable costs represent 87.25% of the total expenses. On the other hand, fixed costs amount to only 12.73% of the total. Labor represents the greatest expense, reaching an average of 71.17% of the total expense. Relative to gross annual revenue, families in class IV reached the highest average numbers with 7,996.00 Bs. (Bolivianos). The lowest gross annual revenues correspond to those in class I with only 3,124.00 Bs. Classes III and II occupy intermediate positions between both former classes. Comparing the sources of gross annual revenue, cattle meat occupies the greatest portion with 40.81%. This is followed by cheese production, lamb, and llama meat with 30.84%, 23.30%, and 2.17% respectively. At the same time, cattle meat and cheese provide these farming families with 71.65% of their total gross annual revenue. The net annual revenues are positive only for families in classes IV and III with numbers at 312.00 and 156.00 Bs. On the other hand, classes II and I have negative net revenues at -3,039.00 and -2,455.00 Bs. The indicative Cost-Benefit Relationship (RBC) shows viability of the activity for families from classes IV and III with figures of 1.04 and 1.02. It is not as viable for families in classes II and I with numbers at 0.62 and 0.50. Estimates provided by the annual investment profitability (RI) are only satisfactory for those in classes IV and III with percentages of 4.6% and 2.13%. Unsatisfactory percentages result for classes II and I with -35.45% and -49.31%. According to the results obtained for the four classes, livestock activity carried out by farming families does not provide an acceptable profitability, even for families that have greater numbers of livestock (more than 12 cattle). It would be much less profitable for the families that have smaller herds of livestock.