Many thousands of shale gas/oil wells have been drilled in the last few years. Valuable drilling expe-rience has been gained and drilling efficiency has been improving continuously. This paper presents the key drilling experience and lessons learned from several shale plays in the US. Well and drilling data of over one thousand wells from Eagle Ford, Haynesville and Marcellus shale plays were retrieved from a database. Analyses of these drilling performance data offer lessons learned and general guidelines of current drilling practices as well as opportunities for improvement. The analyses include gas/oil shale failure mechanisms, mud types, drilling performance data such as drilling days or drilling fluid costs versus depth, mud weight, well architectures such as bit sizes, casing sizes and depths of the casing shoe, as well as lateral lengths. A statistical analysis (P10, P50, P90) was also per-formed to obtain industry-wide drilling performance baselines. Comparisons were made among different mud types on drilling performance and drilling performance among different operating companies. Oil-based mud (OBM) does not always perform better than water-based mud (WBM). For longer wells, it usually takes fewer drilling days for OBM than for WBM. However, for shorter wells and some long wells, certain WBM performs as well as OBM. The analysis showed that our industry has made clear improvements in drilling efficiency over the years and certain operators perform much better than the industry average. The analysis also showed that there is a large variation in total drilling days for similar well depths and trajectories, indicating there is a large oppor-tunity for improvement. One interesting finding is that the top operators can drill wells in fewer days than industry average even though their drilling fluids costs are slightly more expensive than industry average. The analyses and results provided lessons learned and general guidelines for current drilling practices and opportunities of improvement such as drilling fluid selections, mud weight, and well architectures.