This paper discusses the micropile classification, design concept, problems associated with the common installation methods, construction control and performance of theis piling system. Micropiles can be designed as soil frictional piles and rock socketed piles either under tension or compression. Discussions will be addressed on the strain compatibility between the steel reinforcements and the grout under high carrying working load and the effects of grout in rock socketed micropile with permanent casings in the overburden soil. The strain compatibility problem. Construction control is another important aspect to warrant success of the micropiling system. Case histories on the construction problems, such as jointing of the reinforcements, distrurbance to the subsurface materials induced by the different installation techniques and control of grouting operation, will be presented and  discussed. Results of static pile load tests of micropiles are also presenteed. Generally, rock socketed micropiles usually experience very small residual settlement as compared to other piling systems.