Dissertation (MSc Telecommunications Engineering)The study was aimed at assessing the impact of network outage on the Value Added Services (VAS) particularly Mobile-Pesa (M-Pesa) among other (VAS) offered by Vodacom network operator in Tanzania. The study was conducted in Ilala municipal in Dar es Salaam Tanzania. The basic parameters used to assess the network availability were Mean Time To Repair (MTTR), Call Setup Success Rate (CSSR) and Total User Outage Time (TUOT). The parameters like the time to get response from the operator, the time to accomplish one successfully M-Pesa transaction and the number of call attempts managed to make a successful call for M-Pesa were also used to measure the customer level of satisfaction on the M-Pesa service. The structured questionnaire given to 150 M-Pesa customers and agents as well as five key informants (two network engineers, two site engineers and one switching official) were used to obtain the information for this study. Observation was used to asses the quality of service (QoS) of Vodacom network in delivering M-Pesa to the customers. The study has found that M-Pesa customers’ satisfaction was moderate. The QoS on VAS like other service was bellow the recommended level by Tanzania communication QoS regulation of 2011. None of the respondents in all locations involved in the study were satisfied at the stipulated level of service quality. Furthermore the study found that the Vodacom network outage greatly contributes to loss to the operator and to the customers. The results also show that, the Vodacom network is characterized with much busy hours and congestions something which degrades the accessibility of the offered services like MPesa. The Vodacom network operator was advised to reduce the restoration period after failure and to increase the capacity of network so as to sustain more customers and the offered services like M-Pesa.