It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

Fidelity Advisor Technology A (FADTX Quick QuoteFADTX - Free Report) : 0.98% expense ratio and 0.53% management fee. FADTX is part of the Sector - Tech mutual fund category that invests in technology and lets investors own a stake in a notoriously volatile sector, but with a much more diversified approach. With annual returns of 22.47% over the last five years, this fund is a winner.

JPMorgan Disciplined Equity I (JDESX Quick QuoteJDESX - Free Report) . Expense ratio: 0.35%. Management fee: 0.25%. JDESX is a Large Cap Blend fund, targeting companies with market caps of over $10 billion. These funds offer investors a stability, and are perfect for people with a "buy and hold" mindset. This fund has managed to produce a robust 13.54% over the last five years.

MFS Mass Investors Growth Stock R6 (MIGNX Quick QuoteMIGNX - Free Report) . Expense ratio: 0.37%. Management fee: 0.33%. Five year annual return: 14.48%. MIGNX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.