The Independent National Electoral Commission announced that Abiru obtained a total of 89,204 votes to defeat his closest opponent, Babatunde Gbadamosi of the Peoples Democratic Party.
Gbadamosi secured a total of 11,257 votes to emerge second.
Abiru won in all the five local government areas in the senatorial district.
Candidates from 12 political parties are contesting in the Lagos East Senatorial bye-elections while eight candidates are contesting the Kosofe Constituency II, Lagos State House of Assembly by-elections.
The contestants for the senatorial election are Muyiwa Adebanjo, Action Alliance; Ms Mercy Adeoye, African Action Congress, and John Kome, African Democratic Congress.
Others are Adebowale Ogunlaru, Action Democratic Party; Adetokunbo Abiru, All Progressives Congress; Olusola Babatope, Allied Peoples Movement; Mrs Florence Trautman, Labour Party; and Ms Adijat Lawal, New Nigeria Peoples Party.
They also include Babatunde Gbadamosi, Peoples Democratic Party; Akin Olukunle, National Rescue Movement; Saheed Aluko, Social Democratic Party and Taiwo Temitope, Young Progressive Party.
The eight contestants for the Kosofe Constituency II bye-election are John Akerele, AA; Sadiq Olawale, AAC; Wasiu Saheed, APC; Adekunle Oladapo, LP; Muyideen Agoro, NNPP; Ademorin Adelaja, NRM; Sikiru Alebiosu, PDP and Mrs Mary Abojeh, ADC.
The two bye-elections became necessary following the demise of the former occupants who were members of APC.