By the early 1980s, it was already the smallest Italian city to retain trolleybus service (with Carrara second).

[4] The original Chieti trolleybus system was inaugurated on 16 July 1950, in place of an obsolete tramway that had been in operation since 1905.

The system's single line connected Chieti railway station (Stazione FS), located in the valley of the Pescara River (in the large suburb of Chieti Scalo), with the city centre, situated on a hill.

Thus, in 1992, due to the poor condition of the overhead wires, it was deemed necessary to suspend the service until such time as a thorough repair or complete reconstruction could be undertaken.

[1] New substations installed as part of the reconstruction work increased the overhead line voltage from 600 V to 750 V.[2] Line 1 is currently operated as the route Colle dell'Ara (Hospital & University campus) – Piazzale dei Martiri Pennesi (Madonna delle Piane) – railway station (in Chieti Scalo) – city centre – Sant'Anna, with a limited number of trolleybuses, operating on their own only in the morning; in the afternoons and during holidays, the trolleybuses are supplemented with diesel powered buses.