Police executed a search warrant this morning (April 6) at Ebony Jewellers in South Street, Chichester, looking for suspected stolen goods.
Officers from the Chichester Neighbourhood Police Team entered the property before it opened, and a large quantity of jewellery was seized.
A spokesman for Sussex Police said the jewellery would now be examined in order to establish where it had come from.
He added no arrests had been made, and the investigation would continue.
The shop has been closed throughout the day, and employees from nearby shops said there had been a number of police present.