Dealloyed nanoporous gold (NPG) is a macroscopic nanostructured material with interconnected void channels and solid ligaments extending in three dimensions. NPG has an excellent electrical conductivity, mechanical rigidity, chemical stability, biocompatibility, and other unusual properties that are readily applicable in important areas, such as electrocatalysis, sensors, and environmental protection. This chapter focuses on the discussion of recent advances regarding the electrocatalytical properties and associated applications of this new material. NPG itself can function as a high-performance electrode material for either electrocatalysis or sensing, when molecules of interest are electrochemically active on gold. Moreover, the gold surface is compatible with a large number of chemical species, such as foreign metal atoms or biomolecules. NPG can thus work as a unique substrate to construct multifunctional materials with better catalytic performance and efficient previous metal utilization, or to prepare hybrid electrodes with high sensitivity and selectivity, used for chemical or biochemical sensing or environmental monitoring. The continued exploration of new properties and applications for these novel materials is expected to lead to ground-breaking discoveries in important fields such as green energy, environment, health, and biotechnology, where electrochemistry plays critical roles.