Today pipeline inspection through the use of in-line inspection tools is a standard procedure. These inspection tools collect highly precise data regarding the geometry of flaws and defects in the pipe wall. In turn this data is used for fitness-for-purpose investigations, the final goal of the operator being an understanding of the true state of integrity for a given pipeline. Different physical principles are applied during the non destructive testing of pipelines, each with its own set of advantages and disadvantages. Choosing the most suitable non destructive testing technology and therefore in line inspection tool for a given inspection task requires an understanding of these different techniques and their system specific measurement thresholds, accuracies and resolutions. This paper will provide an overview of the most widely used in-line inspection technologies of today, with a special focus on the use of ultrasound technology for the detection and sizing of metal loss, quantitative wall thickness measurement and crack inspection. Case examples will be used to illustrate the information that these tools can provide and the influence of accuracy, resolution and confidence levels on integrity assessment and fitness-for-purpose procedures. The paper will also discuss current trends in the industry: the development and application of specialized inspection tools for offshore pipelines in a deep water environment, the combination of different inspection tasks into a single tool or utilizing a multi-technology approach to optimize inspection performance. The advantages of the multi-technology approach will be illustrated through its use in a new inspection tool combining ultrasound, magnetic flux leakage and eddy current technologies in order to provide true quantitative wall thickness measurement and metal loss inspection capabilities for gas pipelines. Finally the paper will provide an outlook on the future technical trends in the pipeline inspection industry.