The former Atletico Madrid man scored in City's 3-1 win over Everton at the start of the month, before bagging a double in another 3-1 victory - this time against West Ham.
He then ended the month with another goal in the 2-1 loss to Chelsea, taking his season total to the joint-highest eight goals in nine Premier League matches.
The striker's form has helped Manuel Pellegrini's men make their way up the league table, after suffering a disappointing start to the campaign.
Aguero's fellow Argentine Mauricio Pochettino was awarded the Manager of the Month award after his Southampton side also continued to impress.
The Saints were unbeaten in October, beating both Swansea and Fulham 2-0 at home and drawing 1-1 away at Old Trafford against reigning champions Manchester United.
The south coast outfit's displays under the former Espanyol boss have seen them emerge as outside contenders for European football next season, after successfully turning last year's leaky defence into one of the league's meanest.