The inducible transcription factor nuclear factor-kappa B (NF-kappaB) plays a central role in regulation of many immune, inflammatory and carcinogenic responses. While normal activation of NF-kappaB is required for cell survival and immunity, aberrant regulation of NF-kappaB leads to development of many pathological states especially those involved in acute inflammation. Recent advances in our knowledge of the signaling mechanisms those control the activation of NF-kappaB highlights the intriguing aspect of NF-kappaB regulation, namely the ability of many different signal transduction pathways originating from a wide variety of inducing mechanisms to converge on a single target, the NF-kappaB/IkappaB complex. In this review we summarize our current understanding of the NF-kappaB signaling pathways, their role in various cellular responses and the potential of using NF-kappaB as a therapeutic target in modern medicine.