This study was undertaken to establish the framework of biological invasions in Cameroon. Two studies have been conducted on the quantification, occurrence and abundance of the Cassava mealybug (Phenacoccus manihoti) in the Centre Region and the Water hyacinth (Eichhornia crassipes) in the Littoral Region of Cameroon. The studies were carried out in October 2017 simultaneously toward the end of the rainy season when the two species are in their high level of performance in their respective localities. Studies on the invasiveness of the Cassava mealybug were complemented by IITA’s biological control strategy in which the natural enemy (Epidinocarsis lopezi) was introduced in all of sub-saharan Africa as a control agent against P. manihoti For the Water hyacinth in the Littoral, local control methods are being used to contain the weed. The control methods being used do not yield good results because of slow and inadequate means. Satellite images taken in October 2017 show that about 25.52% of its surface area of Douala IV is covered by Water hyacinth, while in Douala V, 1.6% of its surface area and in Bonalea 2.0% of its surface area comparative growth studies have also shown that between 2010 and 2017, the mass of Water hyacinth has increased quantitatively. In spite of the economic values attached to it by some communities, the weed remains a fast invader.