Objective: One of the challenges faced in wireless sensor networks is the constraints in battery power. The main objective of this paper is to address the energy efficiency issue by proposing a real-time routing protocol with controlled dissemination of data queries by mobile sink (RTCD). Methodology: Two phases namely the flooding phase and the routing phase are followed for data collection by mobile sink. A mobile sink helps in efficient data gathering compared to a static sink, reducing the total energy consumption in the network. In the flooding phase, controlled dissemination is achieved by limiting the network diameter and setting a threshold value for residual energy of the nodes. In the routing phase, routing of data is done on the basis of choosing an optimal forwarder having the maximum weighted value of composite link metric, comprising the parameters Packet Reception Rate (PRR), packet one-hop velocity and residual energy of the nodes. Realtime data delivery ensures delivery of packets within deadlines in delay- constrained applications. Findings: Simulations using Network Simulator-2 suggest that the routing phase in RTCD outperforms the reactive, proactive and hybrid routing protocols in terms of QoS parameters such as Packet Delivery Ratio (PDR), Normalized Energy Consumption (NEC) and average end-to-end delay. The reactive, proactive and hybrid routing protocols considered are AODV, DSDV and ZRP respectively. It has been found that PDR for RTCD routing is higher than comparative protocols for large networks. RTCD routing gives intermediate results in case of average end-to-end delay and NEC. Also, the impact of network diameter on Total Energy Consumption (TEC) has been studied which shows that TEC increases with network diameter. An optimum value of 1.8J is set as the threshold value of residual energy of nodes based on the simulation results for controlling the energy consumption.