Malaria transmission studies in the Rufiji River basin have shown that the area is holoendemic. However, there is still paucity in our knowledge on the biology and ecology of the malaria vectors in the lower Rufiji River basin (Rufiji district). Although Anopheles gambiae and An. funestus are known to be the major vectors of malaria in the upper Rufiji basin (Kilombero district), the specific vectors in the lower Rufiji basin are not known for certain. This may compromise the choice of interventions based on vector control. It is, therefore, imperative to understand the diversity and ecology of the vector species and hence the intensity and potential risk of malaria transmission in lower Rufiji Basin, such information is vital for the designing of appropriate control strategies. The information provided by this book is likely to form the basis for improvement of the interventions relevant to lower Rufiji basin and could also be of value in the evaluating changes in malaria transmission and incidence over time in the lower Rufiji basin.