A novel synthesis of N-acryloyl-tris-(hydroxymethyl)aminomethane (NAT) is described. The polymerization kinetics and transparency of the poly(NAT) gels crosslinked by a crosslinker (CL) e.g. N,N'-methylenebisacrylamide (Bis), i.e. poly(NAT + Bis) polymer, are shown. Poly(NAT + Bis) gradient (4-24 %) gels were prepared and found to resolve native proteins according to their size. The exclusion limit of these gels is over 3 x 106 Da. This is more than threefold higher than the exclusion limit of the polyacrylamide gradient gel of the same concentration. Therefore poly(NAT + CL) gels are better than polyacrylamide gels for the resolution of large proteins. It was demonstrated that poly(NAT + CL)-polyacrylamide composite gels could be prepared. The poly(NAT + CL) gels were found to be advantageous also for isoelectric focussing in carrier ampholytes or immobilized pH gradients. Poly(NAT + CL) gels are also very good for separation of nucleic acids. The resolution is particularly good in the range between several hundred to 4-5000 base pairs. Under the optimized conditions, DNA molecules of more than 20 kbases can be perfectly resolved.