This thesis presents investigations into the collision dynamics of cold metastable neon atoms in a magneto-optical trap (MOT). At very cold temperatures (approx. 1 mK) the atomic interaction occurs at long range and cannot be treated classically as the interaction between two nuclear point particles. In addition, the collision dynamics can be considerably altered in the presence of an optical eld. In this thesis results are presented for collisions that are altered by the presence of an optical eld and also collisions where the optical eld can be neglected. Controlled optical collisions of cold, metastable Ne atoms are performed by using a control laser tuned close to the (3s)3P2 to (3p)3D3 cooling transition. The control laser modies the rate of ionizing collisions by promoting a pair of colliding atoms onto an excited state potential. In order to induce collisions between pairs of trapped metastables, a control laser is tuned to the red of the transition where we measure a factor of 4 increase in the rate for ionizing collisions. We also investigate the eect of optical shielding by tuning the laser to the blue of the transition and observe a factor of 5 suppression in the ionization rate. However, the measured ionization spectrum does not contain resonances due to the formation of photoassociated molecules as predicted by Doery et al [1]. Instead, we observe a broad unresolvable ionization spectrum that is well described by established theory [2]. Collision cross sections are measured for neon in the (3s)3P2 metastable state with ground state, thermal atoms and molecules. The technique is based on the measurement of the loss rate due to collisions with a background gas. Generally, these type of collisions are considered undesirable, however, it is possible to infer information about the collision cross section if the rate of collisions is accurately known. This novel technique is described and collision cross section measurements are presented for metastable neon in the (3s)3P2 state with He, Ne, Ar, H2, O2, and N2. The average thermal energy of the collision ranges from 11 meV to 27 meV and the measurements have relatively small errors, of the order of 10%.