Lake Tempe is recorded as one of largest lakes in Sulawesi, Indonesia. The lake is important for local people activities and also for their income sources. Subsequently, the lake and surrounding areas are also important for regional and international necessities, for examples are for water regulation, water sources for household and paddy field, climate change issues and conservation of migratory birds. Several observations were made from 2013 to 2015 is to identify the environmental and social issues related to the sustainable lake management. Interview of informants was done during observation. Subsequently, literature study was made. Sedimentation is occurred at severe level which local people informed that sedimentation rate is reaching 10 cm/yr. It indicated the forest and other natural vegetation in upstream areas are degraded. Fertilizer is used in crop activities at new created land during dry season along the bank of lake. It increased the chemical pollution into the lake and subsequently threat fish and water bird population. Based on observation, most of the fishes caught by fishermen can be considered small in size, which indicate that the fish populations are being over-exploited. The water bird populations are decreased and it should be noted that whistling duck population is become extinct as impact of over-exploitation and illegal poaching. Some noxious species, such as Eichhornia crassipes (aquatic plant), Mimosa pigra (weedy shrub) and Hypostomus sp. (suckermouth catfish) have invested the lake areas. Therefore, the lake sustainability is threatened and good management and action are needed to restore the lake function.