Abstract: The collision of multiple MSG3 transmissions due to the selection of the same preamble sequence in the Long Term Evolution (LTE) Random Access procedure is an important problem which can impact on the performance of cellular Internet of Things (IoT) networks. In this paper, we propose a standard-compatible probabilistic retransmission approach to reduce the number of collisions of MSG3 messages in cellular IoT technologies. In our proposal, every Machine-Type Communications (MTC) device with an uplink grant for retransmitting an MSG3 message uses a probability value to decide whether or not to transmit. Two retransmission policies were proposed to reduce the number of simultaneous MSG3 messages received at the base station. To apply these policies, the estimation of the number of MTC devices trying random access in a given Random Access Opportunity is required. A novel method to estimate this value at the device side is proposed based on Random Access Response (RAR) message counting and the Access Class Barring (ACB) barring probability. Results derived via simulations show that the proposed approach decreases the number of collisions of MSG3 messages, reducing the access delay and energy consumption, as well as decreasing the utilization of the Packet Uplink Shared Channel (PUSCH) when compared to conventional LTE Random Access scheme Ver menos